diff --git "a/raw_rss_feeds/https___arxiv_org_rss_physics.xml" "b/raw_rss_feeds/https___arxiv_org_rss_physics.xml" --- "a/raw_rss_feeds/https___arxiv_org_rss_physics.xml" +++ "b/raw_rss_feeds/https___arxiv_org_rss_physics.xml" @@ -7,2178 +7,3551 @@ http://www.rssboard.org/rss-specification en-us - Mon, 22 Dec 2025 05:00:07 +0000 + Tue, 23 Dec 2025 05:00:21 +0000 rss-help@arxiv.org - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 - Saturday Sunday + Saturday - Effects of the Coriolis force on the coherent structures in conventionally neutral atmospheric boundary layers - https://arxiv.org/abs/2512.16930 - arXiv:2512.16930v1 Announce Type: new -Abstract: It is well known that the Coriolis force due to Earth's rotation can induce wind veer in the mean flow velocity of an atmospheric boundary layer (ABL), but much less is known about its effects on turbulent coherent structures. In this work, large-eddy simulation (LES) is employed to investigate the effects of the Coriolis force on the characteristics of turbulent coherent structures in the conventionally neutral atmospheric boundary layers (CNBL). Variation of the Coriolis force is realized by changing latitude or geostrophic wind speed.We found that the Coriolis force causes distinct deflection of coherent velocity structures to the geostrophic wind direction, which is not aligned with the direction of either the mean wind or the mean shear. By plotting against the difference between the local wind veer angle and the global cross-isobaric angle, the structure deflection angle under different conditions can be well collapsed, indicating a possible universal relationship. Moreover, we also studied the effect of the Coriolis force on the inclination angle of large-scale turbulent structures. It is found that as latitude decreases or geostrophic wind speed increases, the inclination angle in the surface layer increases, probably due to the deflection of turbulent structures caused by the Coriolis force. - oai:arXiv.org:2512.16930v1 - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Changlong Wang, Luoqin Liu, Xiang I. A. Yang, Ruifeng Hu - - - On Energy-Dependent Neutron Diffusion - https://arxiv.org/abs/2512.16931 - arXiv:2512.16931v1 Announce Type: new -Abstract: While the energy-dependent neutron diffusion equation is widely employed in nuclear engineering, its status as an approximation to the transport equation is not yet completely understood, and several different approximations are in use to determine the diffusion coefficients. Past work on the theory underlying the diffusion approximation has often made use of asymptotic arguments; in the energy-dependent case, however, papers have appeared that differ substantially in their findings. Here we present a formal asymptotic derivation of the multigroup diffusion equation which addresses these differences, along with the varying and sometimes physically stringent assumptions employed in these works. - Further, we show a way to exactly invert the relationship between flux and current in the P1 approximation, giving a matricial expression for the multigroup diffusion coefficient which is formally exact, has clear physical meaning, and which can be easily computed to arbitrary precision on the basis of cross-section data already produced by lattice calculations. The resulting 2-group diffusion coefficient for an infinite medium of hydrogen is calculated with Monte Carlo, and compared to the those deriving from the Cumulative Migration Method and from the out-scatter approximation. - oai:arXiv.org:2512.16931v1 - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Gabriele Burgio, Christian Reiter, Stefano Lorenzi - - - Gravitational collapse of a degenerate wormhole - https://arxiv.org/abs/2512.16933 - arXiv:2512.16933v1 Announce Type: new -Abstract: The dynamics of a degenerate spherically symmetric wormhole in a vacuum is considered. An extension of the equivalence principle to matter free objects that are the source of a gravitational field is proposed. Using the Klinkhamer metric as an example, it is shown that a degenerate wormhole is precisely such an object. Application of the extended equivalence principle reduces the radial dynamics of the Klinkhamer wormhole to the dynamics of the radial fall of a test particle in a Schwarzschild gravitational field. It is proven that any bound state of the traversable Klinkhamer wormhole eventually collapses into a nontraversable Einstein-Rosen wormhole. An estimate is presented showing that the traversable Klinkhamer wormhole, although nonstationary, is a longlived state. - oai:arXiv.org:2512.16933v1 + Magnetic flux imaging in a 3D superconductor integrated circuit + https://arxiv.org/abs/2512.17921 + arXiv:2512.17921v1 Announce Type: new +Abstract: We report on imaging magnetic flux distributions in a multilayered superconductor integrated circuit which emerge during magnetization and after field cooling of the circuit in the DC magnetic field. The obtained complicated field maps expose the flux propagation across the patterned superconducting ground planes sandwiching layers with Josephson junction-based logic cells, fine wire grid around the functional units, and multiple superconducting fill structures located in different inner layers. The observed intricate flux distributions are explained by specific patterns of Meissner screening currents and superconducting critical currents in different mutually interacting parts of the integrated circuit. Our results provide important insights into possible ways of improving the protection of superconductor integrated circuits from magnetic fields and their resilience against flux trapping. + oai:arXiv.org:2512.17921v1 physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Juri Dimaschko + http://creativecommons.org/publicdomain/zero/1.0/ + Tong Ren, Andres Glatz, Boldizsar Jank\'o, Justin L. Mallek, Sergey K. Tolpygo, Vitalii K. Vlasko-Vlasov - A Re-Examination Of Foundational Elements Of Cosmology - https://arxiv.org/abs/2512.16934 - arXiv:2512.16934v1 Announce Type: new -Abstract: This paper undertakes a conceptual re-examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann-Lema\^itre-Robertson-Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and translational Killing equations, yielding both the metric \emph{and} its translational generators for $k\in\{-1,0,1\}$ without any further assumptions. We then analyze how continuous symmetries are inherited by the Einstein tensor and the Hilbert energy-momentum tensor, proving two general propositions. Furthermore, we use the Maxwell and Kalb-Ramond fields to show that a homogeneous and isotropic energy-momentum tensor, in general, does \emph{not} give rise to field configurations which share these symmetries. In particular, the Kalb-Ramond field we derive is significantly more general than what is usually encountered in the cosmological context. Finally, we provide a rigorous but accessible, elementary, and transparent derivation of the scalar-vector-tensor decomposition from the linearized Einstein equations. Together, these results highlight the value of multiple complementary formulations of the same cosmological physics. - oai:arXiv.org:2512.16934v1 - physics.gen-ph - gr-qc - Mon, 22 Dec 2025 00:00:00 -0500 + A curated UK rain radar data set for training and benchmarking nowcasting models + https://arxiv.org/abs/2512.17924 + arXiv:2512.17924v1 Announce Type: new +Abstract: This paper documents a data set of UK rain radar image sequences for use in statistical modeling and machine learning methods for nowcasting. The main dataset contains 1,000 randomly sampled sequences of length 20 steps (15-minute increments) of 2D radar intensity fields of dimension 40x40 (at 5km spatial resolution). Spatially stratified sampling ensures spatial homogeneity despite removal of clear-sky cases by threshold-based truncation. For each radar sequence, additional atmospheric and geographic features are made available, including date, location, mean elevation, mean wind direction and speed and prevailing storm type. New R functions to extract data from the binary "Nimrod" radar data format are provided. A case study is presented to train and evaluate a simple convolutional neural network for radar nowcasting, including self-contained R code. + oai:arXiv.org:2512.17924v1 + physics.ao-ph + cs.CV + cs.LG + stat.AP + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Lavinia Heisenberg + http://creativecommons.org/licenses/by-sa/4.0/ + Viv Atureta, Rifki Priansyah Jasin, Stefan Siegert - Exact solution of the two-dimensional (2D) Ising model at an external magnetic field - https://arxiv.org/abs/2512.16935 - arXiv:2512.16935v1 Announce Type: new -Abstract: The exact solution of the two-dimensional (2D) Ising model at an external magnetic field is derived by a modified Clifford algebraic approach. At first, the transfer matrices are analyzed in three representations, i.e., Clifford algebraic representation, transfer tensor representation and schematic representation, to inspect nonlocal effects in this many-body interacting system. It is ensured that nontrivial topological structures exist in this system, which is analogous to (but different with) those in the three-dimensional (3D) Ising model at zero magnetic field. Therefore, the approaches developed for the 3D Ising models are modified to be appropriable for solving analytically the solution of the 2D Ising model at a magnetic field. An additional rotation, serving as a topological Lorentz transformation, is applied for dealing with the topological problems in the present system. The rotation angle for the transformation is determined by Yang-Baxter relations and a subsequent average of rotation angles treating the linear change of the topological actions. Application of a magnetic field increases the magnetization, shifting the critical point to higher temperatures. At the temperature above the critical point, the magnetization keeps zero until a critical field at which it jumps rapidly as a first-order magnetization process. The partition function and the magnetization obtained are helpful for understanding the physical properties, in particular, the magnetization processes of the 2D magnetic materials. - oai:arXiv.org:2512.16935v1 - physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Toward an usage of americium-241 for filter calibration + https://arxiv.org/abs/2512.17927 + arXiv:2512.17927v1 Announce Type: new +Abstract: In nuclear safety and environmental studies, it is necessary to measure the activity of aerosols collected on filters. The calibration of these filters' measurement chains currently involves producing a reference filter with a controlled deposit of aerosol marked by a specific radionuclide. In France, commonly used radionuclides include 137 Cs for gamma or beta emitters, 90 Sr/ 90 Y for beta emitters, and 239 Pu for alpha emitters. However, using 239 Pu presents several issues, notably the destruction of the filter required to determine its traceable activity and the associated uncertainties. The challenge of this project is to propose a radionuclide enabling non-destructive, SI-traceable measurement while retaining the reference filter. The proposed radionuclide is 241 Am, which is both alpha and gamma-emitting and allows for precise non-destructive measurements. Reference filters are produced on the IRSN's ICARE test bench with calibrated aerosols tagged with 241 Am. The reference activity of theses filters is measured by gamma spectrometry on CEA/LNHB reference counter. A series of tests confirmed that 241 Am provides accurate activity determination with minimal uncertainty. Consequently, adopting 241 Am can significantly improve the reliability of radioactive contamination monitoring while avoiding practical challenges associated with plutonium. + oai:arXiv.org:2512.17927v1 + physics.ins-det + nucl-ex + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Zhidong Zhang + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Radioprotection, 2025, 60 (2), pp.203-207 + G. Dougniaux (Asnr, Asnr/Psn-Res/Sca/Lpma), B. Sabot (Lnhb), S. Pierre (Lnhb), B. Dhieux Lestavel (Asnr, Asnr/Psn-Res/Sca/Lpma) - Disentangling the Cosmic/Comoving Duality: The Cognitive Stability and Typicality Tests - https://arxiv.org/abs/2512.16937 - arXiv:2512.16937v1 Announce Type: new -Abstract: Cosmological scenarios wherein the cumulative number of spontaneously formed, cognitively impaired, disembodied transient observers is vastly larger than the corresponding number of atypical `ordinary observers' (OOs) formed in the conventional way -- essentially via cosmic evolution and gravitational instability -- are disqualified in modern cosmology on the grounds of Cognitive Instability -- the untrustworsiness of one own's reasoning -- let alone the atypicality of OOs like us. According to the concordance $\Lambda$CDM cosmological model -- when described in the (expanding) `cosmic frame' -- the cosmological expansion is future-eternal. In this frame we are atypical OOs, which are vastly outnumbered by typical Boltzmann Brains (BBs) that spontaneously form via sheer thermal fluctuations in the future-eternal asymptotic de Sitter spacetime. In the case that dark energy (DE) ultimately decays, the cumulative number of transient `Freak Observers' (FOs) formed and destroyed spontaneously by virtue of the quantum uncertainty principle ultimately overwhelms that of OOs. Either possibility is unacceptable. We argue that these unsettling conclusions are artifacts of employing the (default) cosmic frame description in which space expands. When analyzed in the comoving frame, OOs overwhelmingly outnumber both BBs and FOs. This suggests that the dual comoving description is the cognitively stable preferred framework for describing our evolving Universe. In this frame, space is globally static, masses monotonically increase, and the space describing gravitationally bounded objects monotonically contracts. - oai:arXiv.org:2512.16937v1 - physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Subcellular Metabolic Tracking Using Fluorescent Nanodiamonds Relaxometry + https://arxiv.org/abs/2512.17931 + arXiv:2512.17931v1 Announce Type: new +Abstract: Fluorescent nanodiamonds (FNDs) relaxometry holds promising future for advancement of high spatiotemporal resolution metabolic imaging technology. In this study, we demonstrate a simultaneous integration of spatial position tracking with FND relaxometry to characterize the temporal dynamics of metabolic processes, thereby enhancing the capability to monitor cellular activities over time. To enable targeted metabolic probing in living cells, FNDs were surface-functionalized to achieve specific localization within key organelles, including the nucleus and mitochondria. This strategy not only facilitates subcellular-level metabolic monitoring but also allows for direct comparison between intra- and extranuclear microenvironments within the same living cell, offering substantial potential for elucidating the spatial and functional heterogeneity of cellular metabolism. + oai:arXiv.org:2512.17931v1 + physics.bio-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - 10.3390/astronomy4040025 - Astronomy 2025, 4(4), 25 - Meir Shimon + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1002/adfm.202527416 + Advanced Functional Materials 2025 + Jia Su, Linyu Zeng, Pengyu Chen, Zenghao Kong, Fazhan Shi - Quantum Monogamy with Predetermined Events - https://arxiv.org/abs/2512.16939 - arXiv:2512.16939v1 Announce Type: new -Abstract: The concept of correlation appears straightforward: measurement outcomes coincide, and patterns emerge. For any record of events, the coefficients are uniquely determined. Thus, if correlations change spontaneously, as seen in quantum monogamy, then individual behavior must have changed first. Surprisingly, this is not always true. When two observables are mutually exclusive, they cannot coincide objectively and need to be grouped across time. Yet, sectioning the flow of events into "iterations" is not trivial in this case. Even with blind windows of coincidence, the same order of outcomes can produce different coefficients of correlation, depending on the number of joint measurements. Therefore, quantum monogamy can happen with fixed pre-determined events. A new concept ("subjective correlation") is required to explain this phenomenon. - oai:arXiv.org:2512.16939v1 - physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 + BattMo -- Battery Modelling Toolbox + https://arxiv.org/abs/2512.17933 + arXiv:2512.17933v1 Announce Type: new +Abstract: This paper presents the Battery Modelling Toolbox (BattMo), a flexible finite volume continuum modelling framework in MATLAB\textsuperscript{\textregistered} (\citeproc{ref-MATLAB}{The MathWorks Inc., 2025}) for simulating the performance of electro-chemical cells. BattMo can quickly setup and solve models for a variety of battery chemistries, even considering 3D designs such as cylindrical and prismatic cells. The simulation input parameters, including the material parameters and geometric descriptions, are specified through JSON schemas. In this respect, we follow the guidelines of the Battery Interface Ontology (BattINFO) to support semantic interoperability in accordance with the FAIR principles (\citeproc{ref-fair}{Wilkinson et al., 2016}). The Doyle-Fuller-Newman (DFN) (\citeproc{ref-Doyle1993ModelingCell}{Doyle et al., 1993}) approach is used as a base model. We include fully coupled thermal simulations. It is possible to include degradation mechanisms such as SEI layer growth, and the use of composite material, such as a mixture of Silicon and graphite. The models are setup in a hierarchical way, for clarity and modularity. Each model corresponds to a computational graph, which introduces a set of variables (the nodes) and functional relationship (the edges). This design enables the flexibility for changing and designing new models. The solver in BattMo uses automatic differentiation and support adjoint computation. We can therefore compute the derivative of objective functions with respect to all parameters efficiently. Gradient-based optimization routines can be used to calibrate parameters from experimental data. + oai:arXiv.org:2512.17933v1 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - 10.3390/quantum7040062 - Quantum Rep. 2025, 7(4), 62 - Ghenadie N. Mardari + Xavier Raynaud, Halvor M{\o}ll Nilsen, August Johansson, Eibar Flores, Lorena Hendrix, Francesca Watson, Sridevi Krishnamurthi, Olav M{\o}yner, Simon Clark - How to present and interpret the Feynman diagrams in this theory describing fermion and boson fields in a unique way, in comparison with the Feynman diagrams so far presented and interpreted? - https://arxiv.org/abs/2512.16940 - arXiv:2512.16940v1 Announce Type: new -Abstract: Although the internal spaces describing spins and charges of fermions' and bosons' second-quantised fields have such different properties, yet we can all describe them equivalently with the ``basis vectors'' which are a superposition of odd (for fermions) and even (for bosons) products of $\gamma^{a}$'s. In an even-dimensional internal space, as it is $d=(13+1)$, odd ``basis vectors'' appear in $2^{\frac{d}{2}-1}$ families with $2^{\frac{d}{2}-1}$ members each, and have their Hermitian conjugate partners in a separate group, while even ``basis vectors'' appear in two orthogonal groups. Algebraic multiplication of boson and fermion ``basis vectors'' determines the interactions between fermions and bosons, and among bosons themselves, and correspondingly also their action. Tensor products of the ``basis vectors'' and basis in ordinary space-time determine states for fermions and bosons, if bosons obtain in addition the space index $\alpha$. We study properties of massless fermions and bosons with the internal spaces determined by the ``basis vectors'' while assuming that fermions and bosons are active only in $d=(3+1)$ of the ordinary space-time. We discuss the Feynman diagrams in this theory, describing internal spaces of fermion and boson fields with odd and even ``basis vectors'', respectively, in comparison with the Feynman diagrams of the theories so far presented and interpreted. - oai:arXiv.org:2512.16940v1 - physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 + All in one: holographic microscopy unveils bacterial transport from single cells to population + https://arxiv.org/abs/2512.17938 + arXiv:2512.17938v1 Announce Type: new +Abstract: Prior to pioneer surface adhesion, bacteria have to navigate in flows, often in confined environments. While much is known about their individual swimming dynamics, our understanding of their transport properties at the population level remains limited. This is primarily due to the experimental challenges associated with tracking, in three dimensions and under flow, a large sample of these microorganisms. Here we investigate, through fast digital holographic microscopy (DHM), a suspension of Shewanella oneidensis MR-1 bacteria in a confined Poiseuille flow. Based on the analysis of several thousand Lagrangian trajectories, we first demonstrate the ability of DHM to discriminate between the fraction of bacteria that adhere to walls, those that are only convected by the flow, and those for which motility helps them migrate through the channel and cross streamlines. Focusing on the motile part of the population, we report new experimental results concerning the spatial and orientational distributions across the confinement direction. In the central part of the flow, migration and shear trapping are observed and well described by existing kinetic models. Close to the walls, averaging over the entire motile population clearly shows an accumulation layer but with no net orientational order, which contradicts models that neglect hydrodynamic interactions with solid surfaces. We think that DHM coupled with the analysis of large-scale bacterial populations will help to understand their transfer mechanisms from the bulk to surfaces. + oai:arXiv.org:2512.17938v1 + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - 10.51746/9789612977351 - N. S. Manko\v{c} Bor\v{s}tnik, H. B. Nielsen + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Lucie Klopffer (LCPME, LEMTA), S. Becker (LEMTA), Laurence Mathieu (EPHE, LCPME), Nicolas Louvet (LEMTA) - Constructing de Sitter space and Dark Matter with Dynamical Tension Strings - https://arxiv.org/abs/2512.16941 - arXiv:2512.16941v1 Announce Type: new -Abstract: The string tensions can be dynamical in the modified measure formalism and appear as an additional dynamical degrees of freedom . These tensions may not be universal, instead, each string generates its own tension. We then consider a new bulk field that can couple to the strings, the tension scalar which changes locally the tension along the world sheet. In the case with two string tensions there is a braneworld solution which gives rise to an induced de Sitter space in the brane, avoiding swampland constraints of the standard string theory. Strings with different tension to ours can appear also as Dark Matter and since they share the same space and compactifications as visible matter, they should lead to Dark copies of the standard model, - oai:arXiv.org:2512.16941v1 + The Jacobi's principle of stationary full action and its consequences + https://arxiv.org/abs/2512.17944 + arXiv:2512.17944v1 Announce Type: new +Abstract: The purpose of this article is to extend the applicability of the stationarity principle of the full Jacobi action to non-conservative natural systems and to derive equations of motion corresponding to this extended principle. To this end, in addition to the well-known variation of the Jacobi action with respect to coordinates, we propose independently variating time. Small variations in coordinates and time depend on the point on the true trajectory with the usual boundary conditions. + oai:arXiv.org:2512.17944v1 physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Eduardo Guendelman + Vitaliy Voytik - Forsaking your own: unveiling the delayed recognition of Garfield's work on the "delayed recognition" phenomenon - https://arxiv.org/abs/2512.16943 - arXiv:2512.16943v1 Announce Type: new -Abstract: Delayed recognition (DR) implies that the full scholarly potential of certain scientific papers is recognized belatedly many years after their publication. Such papers are initially barely cited (sleep), and then suddenly, sometime in the future, their citation numbers burst (are awakened). After van Raan (2004a) called them "Sleeping Beauties" the DR phenomenon has drawn considerable attention. However, long before van Raan (2004a) Garfield studied the phenomenon in a series of articles from 1970 up to year 2004. In the present study we ask the pertinent question; Has the phenomenon of DR itself suffered the delayed recognition? In search of an answer we study the citation history of the Garfield (1980a) paper in which Garfield addressed DR directly for the first time. We find that the paper hardly received the attention befitting the Garfield's stature as an information scientist. Specifically, the paper received a meager of 10 citations up to the publication year of van Raan (2004a) and was then, in 2007, feebly awakened from its deep sleep of twenty-eight years receiving 20 citations in next four years; up to 2010. Being the undisputed giant of information science that even Garfield's paper on DR can suffer DR is hardly anticipated. - oai:arXiv.org:2512.16943v1 + Remarks on Legal Entanglement: No-Signaling, Local Operations, and Legal Updates + https://arxiv.org/abs/2512.17947 + arXiv:2512.17947v1 Announce Type: new +Abstract: Godfrey and Sichelman propose a quantum-inspired framework, legal entanglement, to model coupled legal relations and interpretations, with quantitative proxies for modularity and information cost. We identify a specific technical issue in their account of formulative entanglement: legislation is modeled as a local operation on subsystem A that changes the reduced state of a distant entangled subsystem B (rho_B' != rho_B) prior to any measurement at B, presented as a departure from quantum no-signaling. In standard quantum mechanics, however, no-signaling holds for all local, trace-preserving operations, not only unitaries. This note states the correct no-signaling result, locates where the mapping becomes inconsistent, and proposes a repair that preserves the legal intuition: treat legislation as (i) a global update of the rule or constraint structure (altering the admissible state space or observables), and or (ii) an LOCC-style process (local operations plus public dissemination of authoritative classical information). We also connect this to an updating-first perspective that helps separate (a) physical locality or no-signaling from (b) institutional or semantic constraint propagation in legal systems. + oai:arXiv.org:2512.17947v1 physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Tariq Ahmad Mir, Marcel Ausloos - - - From the thermodynamics of irreversible processes to dissipative structures and active matter - https://arxiv.org/abs/2512.16944 - arXiv:2512.16944v1 Announce Type: new -Abstract: A historical perspective is presented on thermodynamics from the pioneering contributions by Carnot and Clausius to recent advances on active matter. Non-equilibrium thermodynamics develops from the identification of the irreversible processes contributing to entropy production in various types of materials and systems. These processes include friction, viscosity, heat and electric conductions, diffusion, reactions, and more. In 1954, Glansdorff and Prigogine formulated a general evolution criterion, which led to the theory of dissipative structures like chemical clocks, reaction-diffusion patterns, and convection patterns. Non-equilibrium statistical mechanics provides the microscopic foundations for the thermodynamics of irreversible processes. - oai:arXiv.org:2512.16944v1 - physics.gen-ph - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Pierre Gaspard + Miko{\l}aj Sienicki, Krzysztof Sienicki - Women in Theoretical Quantum Physics in Brazil:demographics, career profiles, recognition, and leadership - https://arxiv.org/abs/2512.16946 - arXiv:2512.16946v1 Announce Type: new -Abstract: Gender imbalance in Physics remains a persistent global challenge, and Brazil is no exception. While women account for only 24% of Physics faculty in the country, their representation in Quantum Physics is even smaller. In this work, we provide the first comprehensive overview of women working in Theoretical Quantum Physics in Brazil, here referred to as the SheQ (She + Quantum) community. Using data from the CNPq Lattes platform, we identify 93 researchers and analyze their geographic distribution, academic trajectories, scientific productivity, international experience, recognition through awards and fellowships, and engagement with initiatives promoting gender equity. Our results reveal both progress and persistent disparities: SheQ researchers have a strong scientific output, leadership roles, and international training; yet, their recognition through productivity fellowships remains modest, and their involvement in gender-related initiatives, although increasing among younger generations, remains limited. By combining quantitative indicators with institutional perspectives, we highlight structural barriers as well as opportunities for fostering a more inclusive environment in Quantum Physics. his study thus contributes to a broader reflection on how diversity not only promotes fairness but also strengthens creativity, innovation, and scientific progress. - oai:arXiv.org:2512.16946v1 + Physicists Joke + https://arxiv.org/abs/2512.17948 + arXiv:2512.17948v1 Announce Type: new +Abstract: This work presents a reconstructed English edition of the seminal humor anthology \textbf{Physicists Joke} (\textbf{Fiziki Shutyat}), originally published in the USSR in 1966. While the Soviet edition served as a significant cultural artifact of the 1960s, a large portion of its content consisted of Russian translations of articles originally written in English. To avoid the loss of nuance inherent in back-translation, this edition does not simply translate the Russian text. Instead, the original English source materials have been identified and restored from archives of journals such as \textbf{Physics Today}, \textbf{The Journal of Irreproducible Results}, \textbf{New Scientist}, and \textbf{Proceedings of the IEEE}. The specific structural framework of the 1966 book has been preserved, along with English translations of the unique Russian scientific folklore, anecdotes, and editorial interludes compiled by the original Soviet editors. This collection offers a glimpse into the sociology of science and the shared professional culture of the "Golden Age" of mid-20th-century physics. + oai:arXiv.org:2512.17948v1 physics.soc-ph - physics.ed-ph - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + physics.hist-ph + physics.pop-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Tatiana Pauletti, Paula Homem de Mello, Thereza Paiva, Vivian V. Fran\c{c}a + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Igor Halperin - Identifying and understanding obstacles to heating sobriety and thermal comfort in collective housing: Insights from a survey in France - https://arxiv.org/abs/2512.16949 - arXiv:2512.16949v1 Announce Type: new -Abstract: In many countries, central heating systems are widely used in multifamily housing allowing maintenance and costs to be shared. However, these systems often limit residents' control over their own consumption, complicating efforts to reduce energy use and maintain comfort. Despite the growing importance of household energy savings in national and European climate targets, little research has examined user experiences with these systems. This study addresses that gap through an exploratory survey conducted in France. Grounded in scientific literature, technical analyses, and current policy frameworks, the survey was distributed through various channels-including public institutions, online platforms, and field outreach-and collected 403 responses. It examined user difficulties in managing heating, including challenges with controls, bill comprehension, and communication with landlords. It also explored behaviours with high energy-savings impact: reducing heating at night or during absences, window opening, and shutter use. Findings show that many residents face barriers to energy-efficient heating, often due to difficult-to-use controls, limited feedback on consumption, and poor support from landlords or property managers. Those who do not reduce heating at night or when away frequently report these challenges. Participants expressed strong interest in solutions such as personalized advice, real-time feedback, and connected radiator valves to improve comfort, control, and energy management. This work highlights the need to better integrate user experience into multifamily housing energy policies. It provides actionable insights for policymakers and housing providers seeking to enhance comfort and energy savings while supporting France and Europe's broader energy transition goals. - oai:arXiv.org:2512.16949v1 - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Spacetime Dynamics and Local Entropy Balance on Causal Horizons + https://arxiv.org/abs/2512.17961 + arXiv:2512.17961v1 Announce Type: new +Abstract: We propose that spacetime dynamics can be organized by a Planck-scale bookkeeping rule, applied per modular $2 \pi$ interval, that balances the geometric entropy increment $\delta A/4G$ against a reversible modular-energy flow $\delta \langle K\rangle$ and an irreversible Landauer-Bennett cost $\ln 2 \delta N_c$, where $K$ is the (dimensionless) modular Hamiltonian of the chosen region defined relative to the chosen reference state, generating entanglement flow across the local screen and $N_c$ counts logically irreversible classical record updates (registration strokes) on that screen. This "information-geometry ledger" is consistent with the Bekenstein-Hawking area law, and -- when enforced on small causal screens under the standard entanglement-equilibrium assumptions -- recovers the full nonlinear Einstein equation. In FLRW cosmology, the same bookkeeping motivates a two-component vacuum sector $\rho_{vac} = \rho_{\Lambda} + 3 \varepsilon H^2 / 8 \pi G$ when a constant inefficiency parameter epsilon is assumed. + oai:arXiv.org:2512.17961v1 + physics.gen-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Energy and Buildings, 2026, 352, pp.116818 - Enzo Cabezas-Rivi\`ere (UB, I2M), Maxime Robillart (UB, I2M), Aline Barlet (ENSAP Bordeaux), Thomas Recht (UB, I2M), Laurent Mora (UB, I2M), Patrick Sebastian (UB, I2M) + Daegene Song - Fairness, Travel, and Market Potential: An Optimization Framework for NBA Expansion - https://arxiv.org/abs/2512.16968 - arXiv:2512.16968v1 Announce Type: new -Abstract: The National Basketball Association (NBA) is actively considering the addition of two expansion teams, raising the question of how to restructure its conferences and divisions to balance travel efficiency, fairness, and revenue opportunities. This study fills a gap at the intersection of sports operations and strategic league design by providing a quantitative framework for expansion planning. We develop two optimization models: one minimizing total travel distance and another using a Nash Bargaining framework to balance travel burdens while accounting for media market size. Using data from all 30 current franchises and six candidate cities (Seattle, Las Vegas, Montreal, Vancouver, Tampa, and Mexico City), we evaluate 15 pairwise expansion scenarios under alternative season lengths and divisional formats. Results show that while the distance-minimizing model produces geographically tight divisions, the Nash Bargaining model generates more balanced outcomes, particularly for geographically isolated franchises, with only modest efficiency losses. Our study offers a flexible decision support framework for league executives, policymakers, and sports economists. It provides evidence-based insights into how expansion decisions can balance operational efficiency, fairness in competition, and access to major media markets in a multi-billion-dollar sports league. - oai:arXiv.org:2512.16968v1 - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + The Bat Signal + https://arxiv.org/abs/2512.17963 + arXiv:2512.17963v1 Announce Type: new +Abstract: We present a simple experiment that can be run in class or remotely with minimal materials. Students use the principles of geometric optics to create their own versions of the bat signal. + oai:arXiv.org:2512.17963v1 + physics.ed-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Ali Hassanzadeh, Morteza Davari, Dries Goossens + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1119/5.0213457 + Phys. Teach. 62, 612-613 (2024) + Keith Zengel, Anna Klales - Generating temporal networks with the Ascona model - https://arxiv.org/abs/2512.16972 - arXiv:2512.16972v1 Announce Type: new -Abstract: We introduce a new sampling method for continuous-time temporal networks based on queueing processes. In particular, we focus on a Markovian version of the model where the links between nodes are Poisson distributed in time and have exponential duration. We highlight the stochastic properties of these temporal structures and leverage them to design synthetic temporal networks with a controllable level of smoothness, which follow patterns relevant for the validation and interpretation of methods for community, scale, change-point, and periodicity detection. Additionally, we show that imposing assortativity constraints on the samples leads to a continuous-time generalization of stochastic block models. Finally, we describe how variations of the model can be used to sample alternative types of structure and temporal networks, especially discrete-time ones. - oai:arXiv.org:2512.16972v1 - physics.soc-ph - math.PR - physics.data-an - Mon, 22 Dec 2025 00:00:00 -0500 + Achieving angular-momentum conservation with physics-informed neural networks in computational relativistic spin hydrodynamics + https://arxiv.org/abs/2512.17971 + arXiv:2512.17971v1 Announce Type: new +Abstract: We propose physics-informed neural networks (PINNs) as a numerical solver for relativistic spin hydrodynamics and demonstrate that the total angular momentum, i.e., the sum of orbital and spin angular momentum, is accurately conserved throughout the fluid evolution by imposing the conservation law directly in the loss function as a training target. This enables controlled numerical studies of the mutual conversion between spin and orbital angular momentum, a central feature of relativistic spin hydrodynamics driven by the rotational viscous effect. We present two physical scenarios with a rotating fluid confined in a cylindrical container: one case in which initial orbital angular momentum is converted into spin angular momentum in analogy with the Barnett effect, and the opposite case in which initial spin angular momentum is converted into orbital angular momentum in analogy with the Einstein-de Haas effect. We investigate these conversion processes governed by the rotational viscous effect by analyzing the spacetime profiles of thermal vorticity and spin potential. Our PINNs-based framework provides the first numerical evidence for spin-orbit angular momentum conversion with fully nonlinear computational relativistic spin hydrodynamics. + oai:arXiv.org:2512.17971v1 + physics.flu-dyn + gr-qc + hep-ph + nucl-th + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-sa/4.0/ - Samuel Koovely + http://creativecommons.org/licenses/by/4.0/ + Hidefumi Matsuda, Koichi Hattori, Koichi Murase - Irrelevant carrots and non-existent sticks: trust, governance, and security in the transition to quantum-safe systems - https://arxiv.org/abs/2512.16974 - arXiv:2512.16974v1 Announce Type: new -Abstract: Quantum computing poses an urgent and widely recognised threat to global cybersecurity, enabling encrypted government, financial, and healthcare data harvested today to be decrypted in the near future. Transitioning to quantum-safe cryptography is therefore essential, demanding coordinated action across a complex, multi-actor innovation system. Drawing on insights from an expert workshop in Amsterdam, this study develops a socially informed vision for a quantum-safe future and analyses the current innovation landscape to identify critical gaps and the actions needed to address them. We map twelve key actor groups involved in the migration process, finding that regulators exert the strongest direct influence, while standardisation bodies play a crucial indirect role. This research provides one of the first system-level mappings of actors, influence pathways and governance responsibilities shaping the quantum-safe transition, revealing several responsibilities with unclear ownership. Although centred on the Netherlands, our findings are applicable to other national contexts navigating quantum-safe transitions. - oai:arXiv.org:2512.16974v1 + Why Locking Up Cartel Members Does not Work + https://arxiv.org/abs/2512.17973 + arXiv:2512.17973v1 Announce Type: new +Abstract: One of the core strategies to reduce cartel violence is by directly targeting members with law enforcement. Whether targeting leaders, disrupting parts of the organisation, or incarcerating members, the purpose is to reduce the strength of cartels directly. Most security strategies result in increased incarceration rates. Yet its effectiveness in addressing organised crime remains unclear, particularly if it fails to prevent recidivism upon release from jail. Here, a model is constructed to quantify cartel participation across generations, where individuals are recruited, age over time, and exit cartels as victims of a homicide or due to incapacitation, or retirement. Incarcerating cartel members prevents less than 10% of cartel offences. Additionally, doubling penalties would reduce cartel members' potential by less than 5%, thereby challenging proposals for stricter rules. Yet, rehabilitation after prison, often neglected as an integral part of the security strategy, could be more effective in lowering cartel crimes. + oai:arXiv.org:2512.17973v1 physics.soc-ph - cs.CY - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ailsa Robertson, Si\^an Brooke, Sebastian De Haro, Christian Schaffner + Rafael Prieto-Curiel - Numerical study of Lagrangian velocity structure functions using acceleration statistics and a spatial-temporal perspective - https://arxiv.org/abs/2512.17078 - arXiv:2512.17078v1 Announce Type: new -Abstract: A fundamental relation in Lagrangian Kolmogorov theory is concerned with inertial range scaling of the second-order velocity structure function over intermediate time lags at sufficiently high Reynolds numbers. However, the scaling is not well observed, and it is uncertain whether the scaling constant ($C_0$) truly approaches a constant value at asymptotic Reynolds numbers. In this paper, direct numerical simulation of forced isotropic turbulence at Taylor-scale Reynolds numbers between 140 and 1300 is used to help advance understanding in this subject. Uncertainties arising from modest simulation time spans are addressed by expressing the velocity structure function in terms of the acceleration autocorrelation, which suggests that $C_0$ may be sensitive to intermittency effects, leading to a sustained, although weak, Reynolds number dependence. The Lagrangian velocity increment is examined from a spatial-temporal perspective, as a combination of convective (spatial) and local (temporal) contributions, which are subject to a strong but incomplete mutual cancellation dependent on Reynolds number and time lag. The convective increment is strongly influenced by the particle displacement, which is driven by large-scale dynamics and can thus grow into inertial range dimensions in space within just a few Kolmogorov time scales, without fully satisfying classical Lagrangian inertial-range requirements. An overall conclusion in this work is that both the limited range of time scales (narrower than for length scales) and the effects of particle displacements have significant roles in the observed behavior of the second-order Lagrangian velocity structure function. - oai:arXiv.org:2512.17078v1 + Computational considerations for the prediction of airfoil Stall Flutter + https://arxiv.org/abs/2512.18009 + arXiv:2512.18009v1 Announce Type: new +Abstract: This paper presents a comprehensive numerical investigation of a NACA0012 undergoing Stall Flutter Limit Cycle Oscillations (LCO) across distinct fluid dynamics regimes. It accurately models Small Amplitude Oscillations (SAO) in the transitional Reynolds regime and Large Amplitude Oscillations (LAO) in the moderate regime, observed in different experimental campaigns. The SAO analysis servs as a verification of the computational framework against established numerical benchmarks. Crucially, the LAO simulations represent the first documented prediction across the full experimental velocity range correlated against available measured data, addressing a significant literature gap. The predictions fidelity relies on rigorous computational criteria defined through a detailed sensitivity analysis. This demonstrated numerical requirements significantly more demanding than those typically employed for computing static polars or simulating dynamic pitching motion of rigid airfoils, underscoring the severity of the aeroelastic problem. Overall, the results show strong qualitative agreement with experimental observations, successfully reproducing key dynamic stall mechanics and bifurcation phenomena. Quantitatively, however, the simulation systematically over--predicts the critical onset velocity and under--predicts the LCO amplitudes, a discrepancy attributed to reduced aerodynamic excitation peaks. + oai:arXiv.org:2512.18009v1 physics.flu-dyn - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Rohini Uma-Vaideswaran, P. K. Yeung + Nikos Spyropoulos, Marinos Manolesos, George Papadakis - The charm of independent voters - https://arxiv.org/abs/2512.17085 - arXiv:2512.17085v1 Announce Type: new -Abstract: Independent voters play an increasingly decisive role in contemporary elections, yet their collective behavior remains poorly understood. This paper investigates how a minority of voters with greater flexibility in their political preferences influences opinion formation in polarized electorates. Using a modified Deffuant model, we show that even simple heterogeneity in agents' openness to vote switching can generate rich and unexpected collective outcomes: "open-minded" agents may (i) prevent full convergence into established party blocs, (ii) give rise to transient centrist clusters, or (iii) align with the positions of major parties. These dynamics resemble empirical patterns observed among real-world independent voters. Our results demonstrate that small shifts in openness parameters can substantially reshape the macroscopic structure of political competition, offering a simple explanation for oscillatory electoral outcomes and the emergence of unstable centrist or cross-cutting coalitions. - oai:arXiv.org:2512.17085v1 + Equivalent bounded confidence processes + https://arxiv.org/abs/2512.18016 + arXiv:2512.18016v1 Announce Type: new +Abstract: In the bounded confidence model the opinions of a set of agents evolve over discrete time steps. In each round an agent averages the opinion of all agents whose opinions are at most a certain threshold apart. Here we assume that the opinions of the agents are elements of the real line. The details of the dynamics are determined by the initial opinions of the agents, i.e. a starting configuration, and the mentioned threshold -- both allowing uncountable infinite possibilities. Recently it was observed that for each starting configuration the set of thresholds can be partitioned into a finite number of intervals such that the evolution of opinions does not depend on the precise value of the threshold within one of the intervals. So, we may say that, given a starting configuration of initial opinions, there is only a finite number of equivalence classes of bounded confidence processes (and an algorithm to compute them). Here we systematically study different notions of equivalence. In our widest notion we can also get rid of the initial starting configuration and end up with a finite number of equivalent bounded confidence processes for each given (finite) number of agents. This allows to precisely study the occurring phenomena for small numbers of agents without the jeopardy of missing interesting cases by performing numerical experiments. We exemplarily study the freezing time, i.e. number of time steps needed until the process stabilizes, and the degree of fragmentation, i.e. the number of different opinions that survive once the process has reached its final state. + oai:arXiv.org:2512.18016v1 physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Ern\H{o} Buz\'as, Attila Szilva - - - An Interpretable Latent Space reveals changing dynamics of European heatwaves - https://arxiv.org/abs/2512.17097 - arXiv:2512.17097v1 Announce Type: new -Abstract: Due to climate change, heatwaves are becoming more frequent and intense, with western Europe experiencing the strongest trends in the Northern Hemisphere mid-latitudes. Part of the temperature trends are caused by circulation changes, which are not accurately captured in climate models. Here we deploy Deep Learning techniques to classify European heatwaves based on their atmospheric circulation and to study their associated changes over time. We use a Variational Autoencoder (VAE) to reduce the dimensionality of the heatwave samples, after which we cluster them on their extraced features. The VAE is trained on large ensemble climate model simulations and we show that the VAE generalizes well to observed heatwave circulations in ERA5 reanalysis, without the need for transfer learning. The circulation features relevant for heatwaves in ERA5 are consistent with the climate model heatwaves. Regression analysis reveals that the Atlantic Plume type of heatwaves are becoming more frequent over time, while the Atlantic High heatwaves are becoming less frequent. We introduce new and straightforward interpretability methods to study the latent space, including feature importance identification and changes over time. We investigate which circulation features are associated with the most important nodes in the latent space and how the latent space changes over time. For example, we find that the Atlantic Low heatwave shows a deepening of the low pressure system off the Atlantic coast over time. Each heatwave type is undergoing unique changes in their circulation, highlighting the necessity to study each heatwave type separately. Our method can furthermore be used to boost specific aspects of extreme events, and we illustrate how heatwave circulation could change in the future if the current trends persist, with in some cases an intensification of features. - oai:arXiv.org:2512.17097v1 - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + math.CO + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Tamara Happ\'e, Jasper Wijnands, Paolo Scussolini, Peter Pfleiderer, Dim Coumou + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Sascha Kurz - Cryogenic Dielectric Metasurface-Integrated Superconducting Nanowire Single-Photon Detectors - https://arxiv.org/abs/2512.17115 - arXiv:2512.17115v1 Announce Type: new -Abstract: Over the past decade, multi-element superconducting nanowire single-photon detectors (SNSPDs) have emerged as the leading single-photon detection technology due to their exceptional system detection efficiency (SDE), ultrahigh timing precision, negligible dark counts, etc. However, achieving these performances with a \textit{single-element} SNSPD has been an outstanding challenge due to a fundamental trade-off: a large active area is necessary for high SDE, while a smaller area is crucial for higher photon count rates, lower dark counts, and lower jitter. Here, we introduce an all-dielectric cryogenic metalens integrated with a single-element SNSPD to achieve high SDE with a smaller active area. Furthermore, we leverage a bifunctional metalens to demonstrate polarization-resolved photodetection at the telecommunication wavelength theoretically. Integrating multifunctional cryogenic metaurfaces with the state-of-the-art SNSPDs may enable novel capabilities with reduced size, weight, power, cost, and cooling (SWaP-C$^{2}$) requirements. - oai:arXiv.org:2512.17115v1 - physics.optics - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Origins of phase-field crack widening in dynamic fragmentation explained + https://arxiv.org/abs/2512.18022 + arXiv:2512.18022v1 Announce Type: new +Abstract: We investigate dynamic crack propagation and fragmentation with the phase-field fracture approach. The method was chosen for its ability to yield crack paths that are independent of the underlying mesh, thanks to the damage regularization zone. In dynamics, we observe a progressive widening of this regularization zone and attribute it to an unphysical trapping of elastic waves. We show that the damage zones do not represent free boundaries accurately and that wave interactions induce additional damage. We reveal how mass erosion, by conserving the elastic wave speed in the damaged regions, can be used to efficiently reduce the spurious diffusion of damage. Furthermore, we provide numerical evidence that dynamically propagating cracks in the phase-field formulation, both with and without mass erosion, converge to the predictions of linear elastic fracture mechanics. For vanishing regularization length, the crack speed and energy release rate become independent of the phase-field regularization length, provided that this length scale is small enough and the mesh fine enough to resolve the process zone. + oai:arXiv.org:2512.18022v1 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Amir Targholizadeh, Grigoriy Y. Nikulin, Pankaj K. Jha + Shad Durussel, Gergely Moln\'ar, Jean-Fran\c{c}ois Molinari - Secondary Species formed from ionic liquid electrospray ion plume impacts with propellant thin films - https://arxiv.org/abs/2512.17122 - arXiv:2512.17122v1 Announce Type: new -Abstract: The operational lifetime of ionic liquid electrospray propulsion systems is limited by plume-extractor electrode interactions. Over time, propellant accumulation, surface erosion, and electrical shorts degrade the extractor and therefore restrict the total impulse throughput. Characterizing the secondary species generated by plume impacts with deposited ionic liquid is therefore essential to understanding and mitigating these degradation pathways. A surface analysis technique known as Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), in the form of a custom electrospray laboratory diagnostic and an analytical-grade system, yields a comprehensive analysis of secondary ions formed from energetic ion beam impacts with ionic liquid thin-film substrates. Results revealed nearly identical positive secondary ion species for both EMI-BF4 and EMI-Im thin films, whereas EMI-Im produced a more diverse set of negative ions consistent with the greater chemical complexity of its anion. The analytical-grade SIMS spectra revealed many relatively high mass-to-charge ratio secondary ions likely below the detection limit for the laboratory diagnostic, thus shifting the average m/z value to above the monomer mass for most spectra. Finally, optical profilometry analysis reveals an estimated 0.5 nm/min sputter rate for an electrospray ion plume bombarding an ionic liquid thin film. - oai:arXiv.org:2512.17122v1 - physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Long-range electrostatics for machine learning interatomic potentials is easier than we thought + https://arxiv.org/abs/2512.18029 + arXiv:2512.18029v1 Announce Type: new +Abstract: The lack of long-range electrostatics is a key limitation of modern machine learning interatomic potentials (MLIPs), hindering reliable applications to interfaces, charge-transfer reactions, polar and ionic materials, and biomolecules. In this Perspective, we distill two design principles behind the Latent Ewald Summation (LES) framework, which can capture long-range interactions, charges, and electrical response just by learning from standard energy and force training data: (i) use a Coulomb functional form with environment-dependent charges to capture electrostatic interactions, and (ii) avoid explicit training on ambiguous density functional theory (DFT) partial charges. When both principles are satisfied, substantial flexibility remains: essentially any short-range MLIP can be augmented; charge equilibration schemes can be added when desired; dipoles and Born effective charges can be inferred or finetuned; and charge/spin-state embeddings or tensorial targets can be further incorporated. We also discuss current limitations and open challenges. Together, these minimal, physics-guided design rules suggest that incorporating long-range electrostatics into MLIPs is simpler and perhaps more broadly applicable than is commonly assumed. + oai:arXiv.org:2512.18029v1 + physics.comp-ph + cond-mat.mtrl-sci + cs.LG + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Giuliana Caramella Hofheins, Aleksandra B. Biedren, Elaine M Petro + Dongjin Kim, Bingqing Cheng - Realism and Ontology in Quantum Mechanics and String Theory - https://arxiv.org/abs/2512.17124 - arXiv:2512.17124v1 Announce Type: new -Abstract: Dualities in physics have challenged traditional forms of scientific realism by undermining the idea that theories describe a unique underlying ontology. In this paper, we develop a new perspective on scientific realism that responds to this challenge. We argue that while realist commitment remains appropriate at the level of a theory's full formal structure, ontological commitment should be treated as tied to specific empirical contexts rather than to a fixed, real ontology. Our proposal draws inspiration from Dennett's notion of a "compression algorithm" as a defining criterion of a scientific theory. On this basis, we separate realism from ontological commitment. To clarify the stakes of this distinction, we contrast our approach with common core realism, which locates ontology in the invariant structure shared by dual models. Focusing on dualities in quantum mechanics and string theory, we show how our view accommodates ontological pluralism while preserving a robust form of structural realism. - oai:arXiv.org:2512.17124v1 + How physics got its right hand: The origins of chiral conventions in electromagnetism + https://arxiv.org/abs/2512.18040 + arXiv:2512.18040v1 Announce Type: new +Abstract: Why do physicists almost universally take the direction of positive rotation to be counterclockwise, and three-dimensional coordinates to be right-handed? This paper traces the historical development of these chiral conventions, with an emphasis on the physical quantity whose direction became the focal point of this discussion in the mid-1800s, the magnetic field. Though these standards are often reduced to mere mathematical, inconsequential choices, an analysis of the impact of Newton, Maxwell, the London Mathematical Society, and others toward the subject can enhance classroom discussion, not only as a contextual sidebar, but also by emphasizing the influence conventions in physics can have on pedagogy, communication, and scientific advancement. + oai:arXiv.org:2512.18040v1 physics.hist-ph - hep-th - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Richard Dawid, Guilherme Franzmann + Tyler McMaken - Full-Wave Optical Modeling of Leaf Internal Light Scattering Dynamics with Potential Applications for Early Detection of Foliar Fungal Disease - https://arxiv.org/abs/2512.17132 - arXiv:2512.17132v1 Announce Type: new -Abstract: Light interacting with plant leaves undergoes reflection, transmission, scattering, and absorption, which together determine leaf optical properties. Changes in leaf architecture disrupt internal light scattering dynamics and consequently affect photosynthetic performance. Previous studies on internal leaf light scattering have primarily relied on ray-tracing approaches (e.g., Raytran) or radiative-transfer models (e.g., PROSPECT). However, these high-frequency approximations cannot capture diffraction and coherent multiple scattering in wavelength-scale leaf tissues, unlike full-wave electromagnetic simulations. Here, we employ GPU-accelerated Finite-Difference Time-Domain (FDTD) simulations to model internal light scattering dynamics using segmented cross-section image geometries of representative dicot and monocot leaves with wavelength-dependent complex refractive indices. The simulations accurately reproduce the reflectance and transmittance characteristics of healthy leaves, showing strong agreement with the PROSPECT model, with average Lin's concordance values of 0.8962 for dicot leaves and 0.7849 for monocot leaves. We further simulate early-stage necrotrophic fungal infection by modeling melanized hyphae penetrating the cuticle and upper epidermis. Diseased leaves exhibit a pronounced reduction in visible green reflectance and a marked suppression of the near-infrared reflectance plateau, consistent with experimental observations. Remaining discrepancies in the visible band are expected to be reduced through more advanced geometric and material modeling. This proof-of-concept study presents a full-wave FDTD optical modeling framework for plant-leaf light scattering, enabling physics-based analysis of internal scattering before and after early-stage fungal penetration and supporting the use of light scattering as an indicator for pre-symptomatic plant fungal disease detection. - oai:arXiv.org:2512.17132v1 - physics.bio-ph - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Real Time Magnetic Field Line Tracing In The Magnetosphere Via Adaptive Error Bounded Integration + https://arxiv.org/abs/2512.18045 + arXiv:2512.18045v1 Announce Type: new +Abstract: Field line tracing is one of the fundamental computational tools used in the study of the magnetosphere, which helps in many areas including footprint mapping, connectivity analysis and real-time visualisation. This note describes an implementation approach to error-bounded adaptive integration of the field line differential equation (ODE), where an embedded Runge-Kutta pair is used in conjunction with event detection, allowing robust localisation of footprint locations on spacecraft. The method is validated against an analytic dipole field model as well as an international geomagnetic reference field (IGRF)-based geomagnetic configuration. + oai:arXiv.org:2512.18045v1 + physics.geo-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Da-Young Lee, Dong-Yeop Na + Taylan Demir - On early-warning of full versus partial Atlantic overturning circulation collapse - https://arxiv.org/abs/2512.17142 - arXiv:2512.17142v1 Announce Type: new -Abstract: Climate models indicate a possible collapse of the Atlantic Meridional Overturning Circulation (AMOC) even for moderate climate change scenarios. There is considerable uncertainty in its likelihood for a given scenario and the critical global warming threshold. An alternative are early-warning signals (EWS) in AMOC fingerprints, which leverage generic statistical properties before destabilization of a steady state (a saddle-node bifurcation). But an AMOC collapse may be a sequence of partial collapses with shutdown of deep water formation in distinct regions. - A conceptual model is presented featuring a sequential shutdown in two deep water formation regions. Multiple tipping points are present that do not follow the saddle-node normal form. As a result, the choice of the observable used to monitor EWS dramatically influences the prediction of the collapse via EWS. Various trends in EWS for different observables make it hard to determine what type of collapse (partial or full) will follow. - oai:arXiv.org:2512.17142v1 - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Divertor Detachment Characterization in Negative Triangularity Discharges in DIII-D via 2D Edge-Plasma Transport Modeling + https://arxiv.org/abs/2512.18052 + arXiv:2512.18052v1 Announce Type: new +Abstract: Edge fluid modeling of the first divertor-plasma detachment experiments in negative triangularity discharges on DIII-D is presented using the 2D multi-fluid code UEDGE, including cross-field particle drifts. Density scans are performed to reproduce the experimental roll-over of the outer-target ion saturation current and to investigate detachment physics for both forward and reverse toroidal magnetic field configurations. Consistent with experiments, the simulations show that approximately 40% higher density is required to reach detachment onset for forward BT compared to reverse BT, and that deep detachment is not achieved for reverse BT. Comparisons with positive triangularity Ohmic discharges further demonstrate that negative triangularity requires substantially higher densities, at or above the Greenwald limit, to access detachment. The modeling indicates that the increased difficulty of achieving detachment in negative triangularity arises from a shorter midplane-to-target connection length, a reduced outer divertor leg length, and lower cross-field transport compared to positive triangularity configurations. + oai:arXiv.org:2512.18052v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Johannes Lohmann + Menglong Zhao, Filippo Scotti, Thomas Rognlien, Marvin Rensink, Alessandro Marinoni, Dinh Truong, Huiqian Wang, Kathreen Thome, Carlos Paz-Soldan - Am I Confused or Is This Confusing?: Deep Ensembles for ENSO Uncertainty Quantification - https://arxiv.org/abs/2512.17153 - arXiv:2512.17153v1 Announce Type: new -Abstract: Faithful uncertainty quantification (UQ) is paramount in high stakes climate prediction. Deep ensembles, or ensembles of probabilistic neural networks, are state of the art for UQ in machine learning (ML) and are growing increasingly popular for weather and climate prediction. However, detailed analyses of the mechanisms, strengths, and limitations of ensembles in these complex problem settings are lacking. We take a step towards filling this gap by deploying deep ensembles for predictability analysis of the El-Ni\~no Southern Oscillation (ENSO) in the Community Earth System Model 2 Large Ensemble (CESM2-LE). Principally, we show that epistemic uncertainty, modeled by ensemble disagreement, robustly signals predictive error growth associated with shifts in the distributions of monthly sea-surface temperature (SST), ocean heat content (OHC), and zonal surface wind stress ($\tau_x$) anomalies under a climate change scenario. Conversely, we find that aleatoric uncertainty, which remains a popular measure of model confidence, becomes less reliable and behaves counterintuitively under climate-change-induced distributional shift. We highlight that, because ensemble performance improvement relative to the expected single model scales with epistemic uncertainty, ensemble improvement increases with distributional shift from climate change. This work demonstrates the utility of deep ensembles for modeling aleatoric and epistemic uncertainty in ML climate prediction, as well as the growing importance of robustly quantifying these two forms of uncertainty under anthropogenic warming. - oai:arXiv.org:2512.17153v1 - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Fast-Recovery Epitaxial NbN Superconducting Nanowire Single-Photon Detectors with Saturated Efficiency at 1550 nm in Liquid Helium + https://arxiv.org/abs/2512.18063 + arXiv:2512.18063v1 Announce Type: new +Abstract: Achieving both high internal efficiency and fast reset times at elevated temperatures remains challenging due to limited understanding of how film properties govern SNSPD performance. We demonstrate that epitaxial NbN films on sapphire enable simultaneous high efficiency and rapid response. We fabricate and characterize SNSPDs based on these films deposited via DC magnetron sputtering on c-cut sapphire. High-quality epitaxial growth preserves a low electron diffusion coefficient and promotes strong electron-phonon coupling, yielding a high critical temperature and efficient hotspot formation in the dirty limit. X-ray diffraction and transmission electron microscopy confirm epitaxial alignment and lattice order. Nanowires of 20 nm width exhibit saturated internal efficiency at 1550 nm wavelength and short reset times at 4.2 K, enabled by lattice matching and high thermal conductance of the sapphire interface. Ab initio modeling reproduces photon count rates, linking device performance quantitatively to film properties such as diffusivity and electron-phonon coupling. + oai:arXiv.org:2512.18063v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Devin M. McAfee, Elizabeth A. Barnes + Francesca Incalza, Matteo Castellani, Dip Joti Paul, Alejandro Simon, Emma Batson, Davide Mondin, Owen Medeiros, Karl K. Berggren - A Path to Resource Optimization and Technological Innovation: Advancing Space and Climate Research with Bidirectional Technologies - https://arxiv.org/abs/2512.17155 - arXiv:2512.17155v1 Announce Type: new -Abstract: This paper introduces Bidirectional Technologies (BiTs), which is defined as technology that addresses the challenges within the aerospace and climate sectors simultaneously. BiTs presents a means to meet global development agendas, in particular, the United Nations 2030 Agenda for Sustainable Development and the Space2030 Agenda. These frameworks position aerospace innovations as tools to address climate change, explicitly highlighting the shared challenges between both fields. This overlap presents an underexplored opportunity to develop BiTs. To explore this potential, the study conducts an extensive literature review to examine the challenges within four categories in both Earth and space contexts: life support, energy systems, monitoring and exploratory systems, and novel technologies. Key traits that influence the successful development of BiTs are then extracted. Based on these traits, a set of actionable recommendations is proposed to serve as a starting point for policymakers and engineers to adapt technologies beyond single-domain applications. Ultimately, this study presents BiTs as a solution to the interconnected challenges on Earth and in space, offering strategies that advance innovation while contributing to global sustainability efforts. - oai:arXiv.org:2512.17155v1 - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Direct Observation of Energy Transport Dynamics and High Thermal Conductance across Single Solid-Molecule Junctions + https://arxiv.org/abs/2512.18089 + arXiv:2512.18089v1 Announce Type: new +Abstract: Interfaces play a crucial role in energy transport at the nanoscale. However, direct experimental observations of interfacial thermal conductance across molecular junctions have remained challenging due to the high spatiotemporal resolution required for probing. Here, we report dynamic energy transport processes across multi-component molecular junctions observed at the atomic level by employing reflection ultrafast electron diffraction. A clear temporal sequence of energy transfer is revealed at early times following photoexcitation of Au(111) surfaces chemically bonded with self-assembled monolayers (SAMs) of alkanethiols: from the gold surface layer (SL) to the head groups of a SAM and then to the CH2-CH2 methylene lattice. Remarkably, the structural dynamics of the gold SL differ significantly from those of clean gold. Furthermore, the methylene lattice dynamics exhibit chain-length insensitivity but with a length-dependent retention time to reach full thermalization. Quantitatively, we find an agreement in the increased out-of-plane atomic motions between the surface gold atoms and the SAM methylene units, signifying the nature of motion-based coupling for interfacial energy transport. High interfacial thermal conductance (~300 MW/m^2/K) and high thermal conductivity for the methylene lattice (~60 W/m/K) are obtained under the condition of impulsive heating, which provide strong support for previous room-temperature theoretical predictions and also the ballistic nature of intrachain heat transfer. This time- and spatially-resolved experimental approach will enable future quantitative assessment of interfacial energy transport across solid-molecule junctions. + oai:arXiv.org:2512.18089v1 + physics.chem-ph + cond-mat.mes-hall + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Yixuan Cheng, Maheen H. Mufti, Carrie He, Ying Cong Zuo + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Md. Shahriar Hossain Shuvo, Xing He, Mithun Ghosh, Ding-Shyue Yang - Capturing Arbitrary Waveform without Absorption with Synthesis of Complex Frequencies - https://arxiv.org/abs/2512.17156 - arXiv:2512.17156v1 Announce Type: new -Abstract: An arbitrary optical waveform can be synthesized by complex-frequency waves as well as by realfrequency harmonic waves. While single complex-frequency wave with exponentially rising waveform can be perfectly absorbed in lossless structures. Here, we propose that arbitrary waveforms can be captured without any absorption through the synthesis of complex frequencies in a lossless system. The scattering matrix zeros of the system correspond to a set of complex frequencies with exponentially rising waveforms, each of which can be virtually and perfectly absorbed. Thus, an arbitrary waveform, decomposed into these complex frequencies automatically, can be captured without any absorption. Then, in a well-designed coupled cavity system, various waveforms such as exponentially decaying, Gaussian, rectangular, and triangular profiles, are captured with high efficiency. The proposed mechanism has potential applications in enhancing light-matter interactions, optical energy storage, and photonic quantum memory. - oai:arXiv.org:2512.17156v1 - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + MCPlas, a MATLAB toolbox for reproducible plasma modelling with COMSOL + https://arxiv.org/abs/2512.18091 + arXiv:2512.18091v1 Announce Type: new +Abstract: The MCPlas toolbox represents a collection of MATLAB functions for the automated generation of an equation-based fluid-Poisson model for non-thermal plasmas in the multiphysics simulation software COMSOL. Following the development of the new generation of the LXCat platform, all input data are prepared in a structured and interoperable JSON format and can be supplied and validated using existing JSON schemas. The toolbox includes fully transparent, editable MATLAB source code and offers an advanced description of electron transport in addition to commonly used approaches in the plasma modelling community. It supports one-dimensional and two-dimensional modelling geometries employing Cartesian, polar and cylindrical coordinate systems. MCPlas is tested on two reference cases: DC- and RF-driven low-pressure glow discharges in argon. Comparison of MCPlas results with results obtained by employing COMSOL's Plasma Module verifies the reliability of the plasma model implemented by MCPlas and demonstrates the significance of electron transport treatment and boundary conditions applied in the toolbox. Using the same examples, the easy handling of complex reaction kinetic models in MCPlas and the reusability of its JSON input data across different modelling platforms are illustrated. This demonstrates that MCPlas provides a transparent and reproducible workflow for the simulation of non-thermal plasmas using COMSOL. + oai:arXiv.org:2512.18091v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Zhaohua Tian, Yu Tian, Yadi Niu, Qi Liu, Zihan Mo, Haoyang Zhang, Qihuang Gong, Ying Gu - - - Holistic Information Theory of Spatial Remote Sensing Imaging - https://arxiv.org/abs/2512.17163 - arXiv:2512.17163v1 Announce Type: new -Abstract: To address the non-optimal global design caused by the independent optimization of optical lenses, photodetectors, and computational processing subsystems in traditional remote sensing imaging system design, this paper proposes a holistic information theory for spatial remote sensing imaging. This theory integrates the optoelectronic imaging hardware front end and computational reconstruction back end into a unified framework. It establishes a complete spatial imaging chain information transfer model with the objective of obtaining the required effective information. The paper innovatively proposes a quantifiable Modulation Transfer Function (MTF)-Signal-to-Noise Ratio (SNR) product criterion. It demonstrates that the system information transmission ability is determined by the product of MTF and SNR, and that these parameters can compensate for each other to achieve equivalent information transfer. Validation through a high-resolution Earth observation system case shows that under consistent reconstruction mean square error conditions, increasing time delay integration stages reduces optical aperture size and significantly lowers primary mirror mass. Simulations and physical experiments further indicate that by increasing integration time, low-resolution optical systems achieve reconstructed fidelity comparable to high-resolution systems. This verifies that small-aperture optical systems can achieve equivalent imaging performance by enhancing SNR. This theory has been successfully applied in the design of the Jilin-1 satellite constellation, providing a new paradigm for low-cost high-resolution remote sensing systems. - oai:arXiv.org:2512.17163v1 - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Jianan Pan, Junbo Hao, Qixiang Gao, Xing Zhong + Marjan N. Stankov, Daan Boer, Wouter Graef, Kevin van 't Veer, Aleksandar P. Jovanovi\'c, Florian Sigeneger, Detlef Loffhagen, Jan van Dijk, Markus M. Becker - Doppler-induced continuous spectral broadening of ultraviolet lasers - https://arxiv.org/abs/2512.17176 - arXiv:2512.17176v1 Announce Type: new -Abstract: We propose a compact scheme based on ultrafast-rotating phase plates (URPPs) to achieve continuous spectral broadening of ultraviolet lasers. The rapid rotation elements behave as a random oscillator which induces Doppler frequency shift into the ultraviolet lasers. As an example, for a disk-shaped phase plate, with the beam acting on the edge at a radius of 10 cm, a rotation frequency of 1 kHz, and a phase-element size of 10 nm, the continuous spectral broadening reaches 0.07%. Further increasing the rotation speed or reducing the phase-element can lead to greater spectral broadening. When multiple URPPs are arranged in series, the superimposed spatiotemporal modulation further enhances the continuous spectral broadening and achieves more effective speckle smoothing. The scheme is applicable to broadening the independent spectrum of optical frequency combs as well as to the mitigation of laser-plasma instabilities in inertial fusion energy. - oai:arXiv.org:2512.17176v1 - physics.optics - physics.plasm-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Ultra-Wide Bandgap AlGaN Heterostructure Field Effect Transistors with Current Gain Cutoff Frequency Above 85 GHz + https://arxiv.org/abs/2512.18103 + arXiv:2512.18103v1 Announce Type: new +Abstract: We report the design and demonstration of ultra-wide-bandgap (UWBG) AlGaN polarization-graded field-effect transistors (PolFETs) that achieve a current-gain cutoff frequency above 85 GHz and a current density exceeding 1.3 A/mm. Ultra-thin channel and buffer layers were grown epitaxially on AlN substrates, and a reverse-graded AlGaN contact layer was incorporated to reduce the contact resistance to below 1 ohm.mm. With aggressively scaled device dimensions, the AlGaN PolFETs exhibit state-of-the-art high-frequency performance for UWBG transistors. Small-signal modeling reveals both parasitic and transit delays, confirming the benefits of reduced access resistance and enhanced intrinsic transconductance. These results establish a new performance benchmark for UWBG AlGaN devices and demonstrate their strong potential for next-generation millimeter-wave electronics. + oai:arXiv.org:2512.18103v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Huanhuan Wu, Yuhan Liu, Shengqiang Zhong, Yaozhi Yi, Zhuwen Lin, Hongwei Yin, Yilin Xu, Fan Yang, Xiantao Jiang, Yao Zhao + Yinxuan Zhu, Andrew A. Allerman, Ashley Wissel-Garcia, Seungheon Shin, Jon Pratt, Can Cao, Kyle J. Liddy, James S. Speck, Brianna A. Klein, Andrew Armstrong, Siddharth Rajan - Physical Computing at the Data Processing Inequality Limit - https://arxiv.org/abs/2512.17233 - arXiv:2512.17233v1 Announce Type: new -Abstract: Wave-physics-based intelligent sensing has driven multidisciplinary applications from smart industries to decision-making systems. Traditional sensing paradigms transform physical waveforms into human-understandable intermediate representations through preprocessing. Such transformations inherently cause information loss owing to data processing inequality (DPI). Here, we established a theoretical framework for physical computing at the DPI upper limit. Physical computing avoids information loss during preprocessing by directly extracting information from physical waveforms, achieving the theoretical maximum of accessible information as determined by the DPI. Furthermore, physical computing comprehensively utilizes multiple dimensions of physical waveforms, thereby enhancing the upper limit of information capture capability. Electromagnetic sensing experiments have demonstrated that physical computing can achieve 100% sensing accuracy, substantially outperforming traditional sensing paradigms. The proposed theoretical framework of physical computing offers a promising path towards enhancing the information-capture capability of next-generation intelligent sensing systems. - oai:arXiv.org:2512.17233v1 + Scaled Ultra-Wide Bandgap AlGaN Polarization-Graded FET with Ultra-thin Buffer Layer + https://arxiv.org/abs/2512.18107 + arXiv:2512.18107v1 Announce Type: new +Abstract: We report on the design and demonstration of ultra-wide bandgap AlGaN polarization-graded field effect transistors with ultra-thin channels to enable excellent current density and high-frequency performance while significantly reducing thermal resistance. We use polarization-graded AlGaN layers and ultra-thin pseudomorphic AlGaN buffer layers to enable low thermal resistance and excellent structural quality. The polarization-graded field effect transistors (PolFETs) demonstrated here show Imax over 800mA/mm and current/power gain cutoff frequency (fT/fmax) of 26/28 GHz. Small signal modeling and analysis were used to determine parasitic/transit delays, and gate-resistance thermometry was implemented to thermally characterize AlGaN PolFET and benchmark against state-of-the-art AlGaN HEMTs. The ultra-thin AlGaN PolFET showed thermal resistance of 12 K.mm/W, representing a significant reduction from typical AlGaN transistors. These results show state-of-art combination of high current density, excellent fT-LG product for ultra-wide bandgap AlGaN transistors, and superior thermal performance, and highlight the promise of AlGaN transistors for future RF and mm-wave applications. + oai:arXiv.org:2512.18107v1 physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yuhang Zheng, Yang Zhao, Xiuting Zou, Chunyu Zhao, Zhiyi Yu, Zechen Li, Jiaxing Wu, Shaofu Xu, Weiwen Zou + Yinxuan Zhu, Ashley Wissel-Garcia, Kidus Guye, Chandan Joishi, Can Cao, Seungheon Shin, Kyle Liddy, Emils G. B. Jurcik, Agnes Maneesha Dominic Merwin Xavier, Andrew A. Allerman, Brianna A. Klein, Andrew Amrstrong, James S. Speck, Samuel Graham, Siddharth Rajan - Who Connects Global Aid? The Hidden Geometry of 10 Million Transactions - https://arxiv.org/abs/2512.17243 - arXiv:2512.17243v1 Announce Type: new -Abstract: The global aid system functions as a complex and evolving ecosystem; yet widespread understanding of its structure remains largely limited to aggregate volume flows. Here we map the network topology of global aid using a dataset of unprecedented scale: over 10 million transaction records connecting 2,456 publishing organisations across 230 countries between 1967 and 2025. We apply bipartite projection and dimensionality reduction to reveal the geometry of the system and unveil hidden patterns. This exposes distinct functional clusters that are otherwise sparsely connected. We find that while governments and multilateral agencies provide the primary resources, a small set of knowledge brokers provide the critical connectivity. Universities and research foundations specifically act as essential bridges between disparate islands of implementers and funders. We identify a core solar system of 25 central actors who drive this connectivity including unanticipated brokers like J-PAL and the Hewlett Foundation. These findings demonstrate that influence in the aid ecosystem flows through structural connectivity as much as financial volume. Our results provide a new framework for donors to identify strategic partners that accelerate coordination and evidence diffusion across the global network. - oai:arXiv.org:2512.17243v1 - physics.soc-ph - econ.GN - q-fin.EC - Mon, 22 Dec 2025 00:00:00 -0500 + Linear Surprisal Analysis of the H + HI -> H2 + I Abstraction Reaction: Further Demonstration of Kinematic Constraints on Product Energy Distributions + https://arxiv.org/abs/2512.18140 + arXiv:2512.18140v1 Announce Type: new +Abstract: Linear surprisal analysis is applied to state-to-state experimental results for the H-atom abstraction reaction, H + HI -> H2 + I. Contrary to previously reported results that indicated that the products from this reaction were not well fit by a linear surprisal, the reaction can be accurately described by linear surprisal parameters when kinematic energy constraints are taken into account. This is further evidence of the important role mass effects play in the energy disposal of state-to-state reactions and of the quantitative value of a very simple model to predict the maximum energy available to the internal states of the products. + oai:arXiv.org:2512.18140v1 + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Paul X. McCarthy, Xian Gong, Marian-Andrei Rizoiu, Paolo Boldi + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Benjamin Costantino, Teresa Picconatto, Mark Taczak, Carl Picconatto - Asymptotic state of nonlinear Landau damping in one-dimensional plasma - https://arxiv.org/abs/2512.17269 - arXiv:2512.17269v1 Announce Type: new -Abstract: In this work, the asymptotic state of nonlinear Landau damping in one-dimensional plasma has been examined using a quasi-linear model and a second-order symplectic integrator. The dispersion relation of the plateau distribution function for the steady-state solution of the quasi-linear mode is extended to the complex plane and compared with the nonlinear simulation. We determine that the asymptotic state of the collisionless plasma is a multi-wave BGK structure. This structure is characterized by multiple vortices in phase space, which correspond to distinct peaks in the frequency-wavenumber ({\omega}, k) spectrum of the electric field - oai:arXiv.org:2512.17269v1 + Electron Density Depletion in Re-Entry Plasma Flows Using Pulsed Electric Fields + https://arxiv.org/abs/2512.18163 + arXiv:2512.18163v1 Announce Type: new +Abstract: Communication blackout due to the plasma layer creates a critical telemetry gap for re-entry vehicles. To mitigate this, we present the first fully-coupled simulation of high-voltage pulsed discharges interacting with a Mach 24 flowfield. The results demonstrate that the applied electric field generates a large, non-neutral plasma sheath near the cathode, depleting electron density by several orders of magnitude over a distance commensurate with the height of the shock layer. This depletion window effectively reduces the attenuation of a 4 GHz signal from 60% to 4% with a manageable power requirement of 66 W per cm$^2$ of exposed cathode surface. A sensitivity analysis reveals that the sheath topology is governed principally by ion kinetics; specifically, corrections to ion mobility at high reduced electric fields lead to enhanced space-charge shielding and a subsequent contraction of the sheath. Conversely, the sheath structure is largely insensitive to the electron mobility model. Finally, we argue that the present drift-diffusion model likely yields a conservative lower bound for mitigation performance. A kinetic approach accounting for ballistic ion transport and non-local ionization would likely predict thicker sheaths and lower attenuation for equivalent power deposition. + oai:arXiv.org:2512.18163v1 physics.plasm-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yifei Ouyang, Ping Zhu, Chung-Sang Ng + http://creativecommons.org/licenses/by/4.0/ + Felipe Martin Rodriguez Fuentes, Bernard Parent - Vertical velocities in quasigeostrophic laboratory vortices - https://arxiv.org/abs/2512.17324 - arXiv:2512.17324v1 Announce Type: new -Abstract: In the present study, we test the predictions of the {\omega}-Equation against laboratory experiments with direct measurements of the vertical velocity w. Our results are further completed through the use of theoretical models of oceanic vortices, with the aim of helping oceanographers in better quantifying regions of upwelling and downwelling in the ocean. Using a rotating table and density stratification, we investigate non-axisymmetric surface vortices. The predicted vertical velocities calculated from the {\omega}-Equation are relatively small (|w| ~ 20 {\mu}m/s) and primarily appear at the vortex edges, where the vorticity sign changes, acting to restore flow stratification. However, our estimates of w, obtained from the divergence of the horizontal velocity field measured by PIV, are five times larger. This discrepancy is further confirmed by direct particle tracking measurements, which indicate a magnitude of approximately 100 {\mu}m/s for w. To address this inconsistency, we incorporate dissipative terms into the {\omega}-Equation to assess the role of viscous diffusion in enhancing internal recirculation in the vortex and thus vertical velocity magnitude. This hypothesis is favorably tested on a Gaussian vortex model. - oai:arXiv.org:2512.17324v1 - physics.flu-dyn - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Transfer Learning for Analysis of Collective and Non-Collective Thomson Scattering Spectra + https://arxiv.org/abs/2512.18173 + arXiv:2512.18173v1 Announce Type: new +Abstract: Thomson scattering (TS) diagnostics provide reliable, minimally perturbative measurements of fundamental plasma parameters, such as electron density ($n_e$) and electron temperature ($T_e$). Deep neural networks can provide accurate estimates of $n_e$ and $T_e$ when conventional fitting algorithms may fail, such as when TS spectra are dominated by noise, or when fast analysis is required for real-time operation. Although deep neural networks typically require large training sets, transfer learning can improve model performance on a target task with limited data by leveraging pre-trained models from related source tasks, where select hidden layers are further trained using target data. We present five architecturally diverse deep neural networks, pre-trained on synthetic TS data and adapted for experimentally measured TS data, to evaluate the efficacy of transfer learning in estimating $n_e$ and $T_e$ in both the collective and non-collective scattering regimes. We evaluate errors in $n_e$ and $T_e$ estimates as a function of training set size for models trained with and without transfer learning, and we observe decreases in model error from transfer learning when the training set contains $\lessapprox$ 200 experimentally measured spectra. + oai:arXiv.org:2512.18173v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Marine Aulnette, Michael Le Bars, Patrice Le Gal + T. Van Hoomissen, J. Alhuthali, A. M. Ortiz, D. A. Mariscal, R. S. Dorst, S. Eisenbach, H. Zhang, J. J. Pilgram, C. G. Constantin, L. Rovige, C. Niemann, D. B. Schaeffer - High-Resolution Sensing via Quantum States Discrimination - https://arxiv.org/abs/2512.17327 - arXiv:2512.17327v1 Announce Type: new -Abstract: High-resolution sensing plays a significant role in scientific research and industrial production, but the practical implementation is constrained by the physical mechanisms of the sensors. To address the critical limitation, we propose a high-resolution sensing approach based on quantum state discrimination. Distinct from conventional strategies, the proposed approach constructs measurement operators in the orthogonal complement space rather than eigenspace of the eigenstate, thereby notably improving the discriminability among quantum states. Moreover, the experimental results via an optical microcavity demonstrate a potential sensing resolution of 4 $\times$ 10\textsuperscript{-6} \degree C and 18 p$\epsilon$ respectively for temperature and strain, and further verify the feasibility of simultaneous sensing of the two parameters. This work establishs a universal approach for high-resolution sensing, and may be extended to different sensing platforms across various application scenarios. - oai:arXiv.org:2512.17327v1 + A Review of Theory and Practical Considerations of Tunable Diode Laser Absorption Spectroscopy Diagnostics + https://arxiv.org/abs/2512.18201 + arXiv:2512.18201v1 Announce Type: new +Abstract: Tunable Diode Laser Absorption Spectroscopy (TDLAS) has emerged as a versatile and reliable diagnostic tool for measuring temperature, pressure, gas composition, and velocity in power generation and propulsion systems. This paper provides a comprehensive review of TDLAS principles and practical considerations for sensor design and implementation. The discussion begins with a mathematical introduction to the theory of gas absorption including: lineshape modeling and broadening mechanisms, quantitative measurements and challenges, and practical line selection rules. The analysis progresses to wavelength-modulation spectroscopy (WMS), highlighting its advantages in noise rejection and robustness in harsh environments. Furthermore, the calibration-free WMS model and the connection between WMS harmonics and lineshape derivatives is derived. Quantitative measurements through use of multiple harmonics is discussed and challenges surrounding measurement rate are presented. The end of the discussion focuses on practical aspects regarding the implementation of scanned-WMS sensors including laser characterization, background subtraction, and hardware debugging. + oai:arXiv.org:2512.18201v1 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Qi-An Su, Qi Song, Hongjing Li, Kaiwen Fu, Xingyu Wu, Jingzheng Huang, Chuan Wang, Guihua Zeng + Jose Guerrero, Mirko Gamba - How back reaction and hydrogen transport control the performance of hydrogen release from liquid organic carriers - https://arxiv.org/abs/2512.17329 - arXiv:2512.17329v1 Announce Type: new -Abstract: Hydrogen, as a clean energy carrier, is a promising option for sustainable energy storage and utilization, yet its storage and transportation remain challenging. Liquid Organic Hydrogen Carriers (LOHCs) provide a potential solution by enabling the reversible chemical binding and release of hydrogen. However, recent experimental studies have revealed a puzzling inhibition of catalytic activity during LOHC dehydrogenation, associated with the absence of hydrogen bubble formation, reduced hydrogen production rates and significant variability across experiments. In this work, we derive a model to elucidate the mechanisms underlying this inhibition, taking into account both the reversible nature of the hydrogenation-dehydrogenation reaction and the role of transport phenomena. Our results demonstrate that efficient transport of hydrogen away from the catalytic pellet is essential to suppress back-reactions and thereby maximize the performance of porous catalysts. In particular, we demonstrate that two distinct kinetic regimes - with high or strongly inhibited hydrogen production - can arise depending on whether bubble nucleation is enabled or suppressed. Beyond LOHC systems, our findings are applicable to a broader class of reversible reactions, particularly those involving volatile products that can leave the liquid reaction medium in form of bubbles. - oai:arXiv.org:2512.17329v1 + Benchmarking the Impact of Active Space Selection on the VQE Pipeline for Quantum Drug Discovery + https://arxiv.org/abs/2512.18203 + arXiv:2512.18203v1 Announce Type: new +Abstract: Quantum computers promise scalable treatments of electronic structure, yet applying variational quantum eigensolvers (VQE) on realistic drug-like molecules remains constrained by the performance limitations of near-term quantum hardwares. A key strategy for addressing this challenge which effectively leverages current Noisy Intermediate-Scale Quantum (NISQ) hardwares yet remains under-benchmarked is active space selection. We introduce a benchmark that heuristically proposes criteria based on chemically grounded metrics to classify the suitability of a molecule for using quantum computing and then quantifies the impact of active space choices across the VQE pipeline for quantum drug discovery. The suite covers several representative drug-like molecules (e.g., lovastatin, oseltamivir, morphine) and uses chemically motivated active spaces. Our VQE evaluations employ both simulation and quantum processing unit (QPU) execution using unitary coupled-cluster with singles and doubles (UCCSD) and hardware-efficient ansatz (HEA). We adopt a more comprehensive evaluation, including chemistry metrics and architecture-centric metrics. For accuracy, we compare them with classical quantum chemistry methods. This work establishes the first systematic benchmark for active space driven VQE and lays the groundwork for future hardware-algorithm co-design studies in quantum drug discovery. + oai:arXiv.org:2512.18203v1 physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Zhi Yin, Xiaoran Li, Zhupeng Han, Shengyu Zhang, Xin Li, Zhihong Zhang, Runqing Zhang, Anbang Wang, Xiaojin Zhang + + + HiRO-ACE: Fast and skillful AI emulation and downscaling trained on a 3 km global storm-resolving model + https://arxiv.org/abs/2512.18224 + arXiv:2512.18224v1 Announce Type: new +Abstract: Kilometer-scale simulations of the atmosphere are an important tool for assessing local weather extremes and climate impacts, but computational expense limits their use to small regions, short periods, and limited ensembles. Machine learning offers a pathway to efficiently emulate these high-resolution simulations. Here we introduce HiRO-ACE, a two-stage AI modeling framework combining a stochastic version of the Ai2 Climate Emulator (ACE2S) with diffusion-based downscaling (HiRO) to generate 3 km precipitation fields over arbitrary regions of the globe. Both components are trained on data derived from a decade of atmospheric simulation by X-SHiELD, a 3 km global storm-resolving model. HiRO performs a 32x downscaling--generating 3 km 6-hourly precipitation from coarse 100 km inputs by training on paired high-resolution and coarsened X-SHiELD outputs. ACE2S is a $1^\circ \times 1^\circ$ ($\sim$100 km) stochastic autoregressive global atmosphere emulator that maintains grid-scale precipitation variability consistent with coarsened X-SHiELD, enabling its outputs to be ingested by HiRO without additional tuning. HiRO-ACE reproduces the distribution of extreme precipitation rates through the 99.99th percentile, with time-mean precipitation biases below 10% almost everywhere. The framework generates plausible tropical cyclones, fronts, and convective events from poorly resolved coarse inputs. Its computational efficiency allows generation of 6-hourly high-resolution regional precipitation for decades of simulated climate within a single day using one H100 GPU, while the probabilistic design enables ensemble generation for quantifying uncertainty. This establishes an AI-enabled pathway for affordably leveraging the realism of expensive km-scale simulations to support local climate adaptation planning and extreme event risk assessment. + oai:arXiv.org:2512.18224v1 + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Tatiana Nizkaia, Thomas Solymosi, Paolo Malgaretti, Peter Wasserscheid, Jens Harting + W. Andre Perkins, Anna Kwa, Jeremy McGibbon, Troy Arcomano, Spencer K. Clark, Oliver Watt-Meyer, Christopher S. Bretherton, Lucas M. Harris - Influence of plasma shaping on the parity of core-localized toroidal Alfv\'{e}n eigenmode in an advanced tokamak configuration - https://arxiv.org/abs/2512.17337 - arXiv:2512.17337v1 Announce Type: new -Abstract: Toroidal Alfv\'{e}n eigenmodes (TAEs) and energetic particle modes (EPMs) can both be excited by energetic particles from auxiliary heating and fusion-born alpha particles in a tokamak. Using the hybrid kinetic-MHD model implemented in the NIMROD code, the excitation of these modes and their properties are investigated in an advanced tokamak configuration with reversed magnetic shear in the core region. The dominant TAE/EPM is found to exhibit odd parity with an anti-ballooning structure when the plasma has elongated, non-circular two-dimensional shaping. As the plasma shaping becomes more circular with reduced elongation, the mode parity undergoes a transition to even parity accompanied by a ballooning structure. These results may help explain the dominant parity of TAE/EPMs observed in advanced tokamak configurations with different plasma shaping. - oai:arXiv.org:2512.17337v1 - physics.plasm-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Performance of Flamelet Models with Epsilon Tracking for Diffusion Flame Simulations + https://arxiv.org/abs/2512.18229 + arXiv:2512.18229v1 Announce Type: new +Abstract: This work examines the physical consistency of the conventional Flamelet Progress Variable (FPV) model for diffusion flame simulations and and introduces a new compressible flamelet formulation that employs the turbulent kinetic energy dissipation rate, $\epsilon$, as the tracking variable. Two-dimensional Reynolds-averaged Navier-Stokes (RANS) simulations are conducted for a reacting, transonic, turbulent mixing layer to assess the coupling between resolved-scale and subgrid flamelet quantities, with emphasis on the role of strain rate. The FPV model is found to decouple resolved-scale and subgrid strain rates, leading to the preferential selection of equilibrium flamelet solutions in regions of high strain and resulting in nonphysical predictions of heat release and species composition. The proposed $\epsilon$-based formulation restores physical consistency by relating the subgrid flamelet strain rate to $\epsilon$, allowing the flamelet to respond to the local resolved-scale strain field. The inclusion of resolved-scale species transport enables advective and diffusive redistribution of products across locally quenched regions. The results indicate that $\epsilon$ offers a physically consistent tracking variable that connects the sub-grid flamelet model to resolved-scale RANS computations. + oai:arXiv.org:2512.18229v1 + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shiwei Xue, Ping Zhu, Haolong Li + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Sylvain L. Walsh, Yalu Zhu, Feng Liu, William A. Sirignano - SPIDER, a Waveform Digitizer ASIC for picosecond timing in LHCb PicoCal - https://arxiv.org/abs/2512.17355 - arXiv:2512.17355v1 Announce Type: new -Abstract: We present the architecture, design and first test results of SPIDER, the first prototype of a TSMC CMOS 65 nm ASIC designed for the time measurement path of LHCb Electromagnetic Calorimeter after LS4 Upgrade. - The main requirements for the readout of this detector are a time resolution below 15 ps rms above 5 GeV, and a channel occupancy up to 30\% (12 Mevent/s). - The first prototype called SPIDER\_V0 is a 2-channel waveform digitizer locked on the LHC clock allowing precise time reconstruction by digital algorithms. The architecture is based on 2 DLLs in series controlling respectively the phase of the sampling window and the sampling frequency, the latter covering the range between 2 and 20 GS/s. Each self-triggering channel houses 8 banks of 32 analog memory cells and a massively parallel Wilkinson ADC for conversion at 5 GHz over 10 bits with a maximal conversion time of 200 ns. - SPIDER targets not only LHCb, but all fast detectors mounted on current and future accelerators. Its sampling frequency can indeed be adjusted to different signal risetimes. Its main frequency of 40 MHz could even be eventually locked to another value by modifying only one of the DLLs in the chip design. - oai:arXiv.org:2512.17355v1 - physics.ins-det - hep-ex - Mon, 22 Dec 2025 00:00:00 -0500 + Flamelet Model with Epsilon Tracking in a Turbine Stator + https://arxiv.org/abs/2512.18235 + arXiv:2512.18235v1 Announce Type: new +Abstract: Combustion within a two-dimensional turbine stator passage is numerically investigated in the context of the turbine-burner concept using a Reynolds-Averaged Navier-Stokes framework coupled with a novel flamelet model. The formulation links resolved-scale turbulence quantities with subgrid flamelet dynamics through the local turbulent kinetic energy dissipation rate, $\epsilon$, which determines the flamelet inflow strain rate. For the first time, combustion of JP-5 is considered in a turbine stator passage as a practical fuel. This is achieved by solving transport equations for 14 major species on the resolved scale, while chemical source terms are obtained from precomputed flamelet libraries based on the HyChem A3 mechanism comprising 119 species and 841 elementary reactions. Model performance is assessed against methane combustion using both a one-step kinetics model and an $\epsilon$-based flamelet formulation employing a 13-species skeletal mechanism. The $\epsilon$-based formulation predicts lower peak flame temperatures due to dissociation effects and approximately 50\% lower net chemical energy addition per unit mass compared with the one-step model, as a result of flame stand-off and downstream strain-rate-induced quenching. For JP-5, the simulations capture combined endothermic pyrolysis and exothermic oxidation processes, leading to vertically displaced reaction zones, increased near-wall temperatures, and larger resolved-scale reaction regions due to the higher flamelet flammability limit relative to methane. + oai:arXiv.org:2512.18235v1 + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Ludovic Alvado, Nicolas Arveuf, Edouard Bechetoille, Guillaume Blanchard, Dominique Breton, Baptiste Joly, Laurent Leterrier, Jihane Maalmi, Samuel Manen, Herv\'e Mathez, Christophe Sylvia, Philippe Vallerand, Richard Vandaele + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Sylvain L. Walsh, Yalu Zhu, Feng Liu, William A. Sirignano - Quantitative phase nano-imaging with a laboratory source - https://arxiv.org/abs/2512.17357 - arXiv:2512.17357v1 Announce Type: new -Abstract: Investigating the structure of matter at the nanoscale non destructively is a key capability enabled by X-ray imaging. One of the most powerful nano-imaging methods is X-ray ptychography, a coherent diffraction imaging technique that has become the go-to method at synchrotron facilities for applications ranging from brain imaging to battery materials. However, the requirements in terms of X-ray beam quality have limited its use to large synchrotron facilities and, to date, only one attempt has been made to translate the technique to a small-scale laboratory. To unleash the power of this technique to the broad user community of laboratory X-ray sources, there are outstanding questions to answer including whether the quantitativeness of the information is preserved in a laboratory despite the drastic decrease in X-ray flux of several orders of magnitude, with respect to synchrotron instruments. In this study not only we demonstrate that the quantitativeness of X-ray ptychography is preserved in a laboratory setting, but we also apply the method to the imaging of a brain tissue phantom. Finally, we describe the current challenges and limitations, and we set the basis for further development and future directions of quantitative nano-imaging with laboratory X-ray sources. - oai:arXiv.org:2512.17357v1 + Super-Poissonian Squeezed Light in the Ground State of Strongly Coupled Light-matter Systems + https://arxiv.org/abs/2512.18242 + arXiv:2512.18242v1 Announce Type: new +Abstract: Strong light-matter coupling enables hybrid states in which photonic and electronic degrees of freedom become correlated even in the ground state. While many-body effects in long-range dispersion interactions are known to reshape electronic properties under such conditions, their impact on quantum-optical observables remains largely unexplored. Here, we address this problem using quantum electrodynamical density-functional theory (QEDFT) combined with the recently developed photon-many-body dispersion (pMBD) functional, which can capture higher-order electron-photon correlations and multi-photon processes. We compute ground-state photonic observables including photon number fluctuations, second-order correlations, and quadrature variances, and find squeezing and super-Poissonian photon statistics emerging from light-matter interactions in the strong coupling regime. Our results demonstrate that capturing the full hierarchy of many-body, electron-photon and multi-photon correlations is essential for a consistent description of quantum-optical properties in strongly coupled molecular systems, establishing QEDFT as a first-principles framework for predicting nonclassical photonic features in the ground state of complex systems. + oai:arXiv.org:2512.18242v1 + physics.chem-ph + cond-mat.mtrl-sci physics.comp-ph - physics.ins-det - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Luca Fardin, Chris Armstrong, Alberto Astolfo, Sebastian Ignacio Allen Binet, Matthieu N. Boone, Rebecca Fitzgarrald, Yong Ma, Alexander Thomas, Darren J. Batey, Alessandro Olivo, Silvia Cipiccia + Cankut Tasci, Mohammad Hassan, Leon Orlov-Sullivan, Leonardo A. Cunha, Johannes Flick - Accelerating field decay along nonlocal metasurfaces by suppressing the Norton wave - https://arxiv.org/abs/2512.17361 - arXiv:2512.17361v1 Announce Type: new -Abstract: Studying the nature of electromagnetic fields of dipole sources over a homogeneous flat ground or impedance surfaces has a long history. In general, at a long distance $r$ from the source, the near-surface field is mostly contributed by the geometrical optics term (describing the radiation pattern), a guided wave, and the higher-order reactive contribution referred to as the Norton wave. In the special case of a perfect magnetic conductor interface, the first two terms vanish, so the residual Norton wave determines the steepest achievable field decay profile of $~r^{-3/2}$ (for a two-dimensional horizontal magnetic dipole). In this letter, we reveal that in the presence of a nonlocal metasurface described by the second-order impedance boundary condition, the field decay can be further accelerated by suppressing the Norton wave (approaching the profiles $r^{-5/2}$ and $r^{-7/2}$ for electric and magnetic fields, respectively). In a proposed practical realization of a nonlocal metasurface, the effect is numerically verified and shown to reduce the edge diffraction effects by 10 dB for the shield diameter of only one wavelength, paving the way toward compact antenna systems. - oai:arXiv.org:2512.17361v1 - physics.optics + Simplified Analytical Models for High-Precision Open-Loop Scanning in Atomic Force Microscopy + https://arxiv.org/abs/2512.18252 + arXiv:2512.18252v1 Announce Type: new +Abstract: Atomic force microscopy (AFM) enables nanoscale characterization and has been widely applied across diverse systems. In AFM, the tip or sample is typically scanned using piezoelectric scanners, which convert applied voltages into precise mechanical displacements with sub-nanometer accuracy and high bandwidth. However, because piezo elements exhibit nonlinear responses, actual displacements can deviate from the applied driving signal by up to 20-30%. Various methods have been developed to improve positional accuracy, but they often suffer from limited scan speed, increased noise, or complex calibration procedures. From the perspective of routine maintenance, ease of calibration is more advantageous for applications where an error of around 1-2% is acceptable, especially when measuring dynamic molecular motions. Motivated by this, we developed a simple method to generate scan waveforms via software-based feedforward control, which can be easily implemented and calibrated. We identify four distinct sources of positioning error in piezo scanners and demonstrate that these errors can be compensated, achieving more than an order-of-magnitude improvement in positioning accuracy compared with uncompensated operation. Because the proposed method requires no additional hardware and is entirely software-based, it does not deteriorate imaging speed and is compatible with a wide range of AFM systems as well as other scanning probe microscopies. + oai:arXiv.org:2512.18252v1 physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Alexander Zhuravlev, Dmitry Tatarnikov, Yury Kurenkov, Stanislav Glybovski1 + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Kenichi Umeda, Noriyuki Kodera - Supersampled scanning transmission X-ray microscopy for high-resolution vibration-free imaging - https://arxiv.org/abs/2512.17366 - arXiv:2512.17366v1 Announce Type: new -Abstract: Scanning transmission X-ray microscopy (STXM) is a nanoscale imaging technique that can utilize several powerful contrast mechanisms for the quantitative mapping of chemical and physical materials properties. Spatial resolutions down to 7~nm at the soft X-ray energy range have been demonstrated. A limiting factor for high-resolution STXM imaging is given by the positioning precision of the sample with respect to the focusing optic, with the current state-of-the-art leading to significant overheads, especially at low pixel dwell times, and being vulnerable to unavoidable external vibrations sources. In this work, we present a method, called supersampled scanning microscopy, that allows for a significant reduction of overhead times while simultaneously removing the effects of vibrational noise by sampling the position of the sample at a rate significantly higher than the vibration spectrum and reconstructing the sample transmission image from the recorded list of positions and detector counts. We demonstrate the performance of the technique with a set of proof-of-concept high-resolution imaging experiments. - oai:arXiv.org:2512.17366v1 - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 + What is Stochastic Supervenience? + https://arxiv.org/abs/2512.18257 + arXiv:2512.18257v1 Announce Type: new +Abstract: Standard formulations of supervenience typically treat higher level properties as point valued facts strictly fixed by underlying base states. However, in many scientific domains, from statistical mechanics to machine learning, basal structures more naturally determine families of probability measures than single outcomes. This paper develops a general framework for stochastic supervenience, in which the dependence of higher level structures on a physical base is represented by Markov kernels that map base states to distributions over macro level configurations. I formulate axioms that secure law like fixation, nondegeneracy, and directional asymmetry, and show that classical deterministic supervenience appears as a limiting Dirac case within the resulting topological space of dependence relations. To connect these metaphysical claims with empirical practice, the framework incorporates information theoretic diagnostics, including normalized mutual information, divergence based spectra, and measures of tail sensitivity. These indices are used to distinguish genuine structural stochasticity from merely epistemic uncertainty, to articulate degrees of distributional multiple realization, and to identify macro level organizations that are salient for intervention. The overall project offers a conservative extension of physicalist dependence that accommodates pervasive structured uncertainty in the special sciences without abandoning the priority of the base level. + oai:arXiv.org:2512.18257v1 + physics.hist-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Simone Finizio, Benjamin Watts, Benedikt R\"osner, J\"org Raabe + Youheng Zhang - In situ substrate birefringence characterization in gravitational wave detectors using a heterodyne polarimetry method - https://arxiv.org/abs/2512.17395 - arXiv:2512.17395v1 Announce Type: new -Abstract: High-quality test mass substrates play essential roles in laser interferometric gravitational wave detectors. Inhomogeneous birefringence distribution in test mass substrates, however, can degrade the sensitivity of the detector by introducing the optical loss and disturbing the interferometer controls. In this paper, we present a heterodyne polarimetry method that enables in situ birefringence characterizations, hence diagnosing the gravitational wave interferometer. We experimentally demonstrate the proposed method with a tabletop setup. We also discuss its applicability to current and future gravitational wave detectors and the detectable limit. - oai:arXiv.org:2512.17395v1 - physics.ins-det - astro-ph.IM - gr-qc - Mon, 22 Dec 2025 00:00:00 -0500 + Growth of Phaseolus vulgaris in Response to Seed Priming by Plasma-Activated Water in Laboratory Screening and Outdoor Pot Trial + https://arxiv.org/abs/2512.18285 + arXiv:2512.18285v1 Announce Type: new +Abstract: This study explores plasma-activated water (PAW) effects on Common bean growth in laboratory and pot trials. Three treatments were assessed: PAW priming, spraying, and their combination. Laboratory trials showed no germination improvement. However, pot trials revealed notable increases in seedling length, biomass, and antioxidant enzyme activity. Enzymes SOD, G-POX, CAT, APX, and GR showed significantly higher activity in PAW-treated plants. These effects were linked to reactive oxygen and nitrogen species in PAW. Findings suggest PAW enhances bean growth and physiology, supporting field farming applications. + oai:arXiv.org:2512.18285v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Satoshi Tanioka, Terri Pearce, Yuta Michimura, Kazuhiro Agatsuma, Martin Van Beuzekom, Alberto Vecchio, Stephen Webster, Matteo Leonardi, Keiko Kokeyama + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1002/ppap.70103 + Mustafa Ghulam, Ramin Mehrabifard, Adriana Mi\v{s}\'uthov\'a, Zuzana Luka\v{c}ov\'a, Pratik Doshi, Zdenko Machala, Bo\v{z}ena \v{S}er\'a - On the essential structure of exact traveling-wave solutions in viscoelastic flow - https://arxiv.org/abs/2512.17407 - arXiv:2512.17407v1 Announce Type: new -Abstract: We examine elastic travelling-wave (`arrowhead') solutions in a viscoelastic, unidirectionally body-forced flow, focusing on their existence and morphological changes as the Weissenberg number, $\mathrm{Wi}$, and streamwise duct length, $L$, are varied. We find that branch topology varies from an isola at low $L$ through a two-sided reconnection at intermediate $L$ to a branch which exists at asymptotically large $\mathrm{Wi}$ for larger $L$. At intermediate $L$ more than two arrowhead solutions can coexist at a given $(\mathrm{Wi}, L)$ choice due to extra saddle node bifurcations. Secondly, the canonical arrowhead consists of two legs joined by an arched head that blocks throughflow and traps a counter-rotating vortex pair, while a polymer strand can emerge as a by-product of a strong extensional region attached/detached to the arrowhead arch. Thirdly, a minimal domain length $L_{\min}$ required to sustain an arrowhead is found to vary non-monotonically with $\mathrm{Wi}$; for $\mathrm{Wi}\ge 20$, detached-strand states control $L_{\min}$ with a relation $L_{\min}\approx 0.125\mathrm{Wi}+1.5$. And fourthly, in sufficiently long domains, the upper branch becomes a localised single arrowhead whose streamwise extent depends on $\mathrm{Wi}$, whereas the lower branch can proliferate into a train of arrowheads at high $\mathrm{Wi}$, a phenomenon not previously reported. - oai:arXiv.org:2512.17407v1 - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + A neural network-based observation operator for weather radar data assimilation + https://arxiv.org/abs/2512.18289 + arXiv:2512.18289v1 Announce Type: new +Abstract: In three-dimensional variational data assimilation (3DVar) for numerical weather prediction (NWP), the observation operator $\mathcal{H}$ plays a central role by mapping model state variables to an observation equivalent. For weather radar, however, specifying $\mathcal{H}$ is particularly challenging: reflectivity is a nonlinear, microphysics-dependent diagnostic quantity that only indirectly relates to the model's prognostic variables, making traditional parameterised radar operators complex, regime-dependent and difficult to tune. In this study, we propose a neural-network (NN)-based observation operator for radar reflectivity and apply it within a 3DVar framework. Using five years (2019-2023) of radar reflectivity data from the Lisca radar and 4.4 km-resolution short-range forecasts from ALADIN model over Slovenia, we train a convolutional encoder-decoder neural network to map model temperature, humidity, horizontal wind components and surface pressure fields to radar reflectivity. Across independent test cases spanning clear-sky, stratiform, and convective regimes, the NN-based operator accurately reproduces the spatial structure and intensity of observed reflectivity, relying primarily on the model state near the observation point. In the extreme precipitation case, which caused widespread floods in Slovenia on August 4, 2023, assimilating the full radar disc reduces the domain-averaged reflectivity root-mean-square error from 5.99 dBZ to 3.47 dBZ and improves the alignment between the analysed and observed convective bands. Embedded within 3DVar, the Jacobian of the NN observation operator allows radar reflectivity observations to inform model state variables, producing corresponding analysis increments. The proposed NN radar observation operator offers a flexible alternative to traditional parameterised radar operators for improving convective-storm forecasts. + oai:arXiv.org:2512.18289v1 + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Lu Zhu, Rich. R. Kerswell + http://creativecommons.org/licenses/by/4.0/ + Marco Stefanelli, \v{Z}iga Zaplotnik, Gregor Skok - Tailored Zn(1-x)TixAl2O4 Nanocomposite Particles via Sol-Gel Route for High-Performance Humidity Sensing - https://arxiv.org/abs/2512.17439 - arXiv:2512.17439v1 Announce Type: new -Abstract: Humidity sensors play a vital role in industrial, healthcare, agricultural, and environmental applications; however, conventional sensors often suffer from issues like low sensitivity, slow response, and poor stability. This study investigates sol-gel synthesized Zn0.85Ti0.15Al2O4 nanocomposite ceramics for high-performance humidity sensing. X-ray Diffraction (XRD) analysis confirms a nanocrystalline structure, while the optical bandgap of 3.76 eV indicates the enhanced sensing potential. The sensor exhibits a significant decrease in resistance, from 500 M{\Omega} (15% RH) to 90 M{\Omega}(90% RH), with fast response (50 s) and recovery times (50 s). Low Hysteresis values (5.86% at 30% RH, 7.69% at 60% RH, and 4.28% at 90% RH) highlight high sensitivity, stability, and repeatability. These results indicate the potential of Zn0.85Ti0.15Al2O4as a promising material for next-generation resistive humidity sensors suitable for commercial and industrial deployment. - oai:arXiv.org:2512.17439v1 + Contactless micro-elastography of single cells using oscillating microbubbles as shear wave sources + https://arxiv.org/abs/2512.18294 + arXiv:2512.18294v1 Announce Type: new +Abstract: The mechanical properties of cells play key roles in their physiology, function, physiological and pathological transformations. Micro-elastography has recently emerged as a promising tool to estimate cellular viscoelastic properties within a millisecond, without the need for mechanical modeling. Here, we report a fully contactless approach to single-cell micro-elastography, using acoustically oscillating gas microbubbles positioned near individual cells (20~\textmu m diameter megakaryocytes) as localized shear wave sources. Using this approach, we successfully performed micro-elastography on cells up to five times smaller than those studied in previous works, establishing the smallest single-cell elastography measurements to date. Spherical or non-spherical bubble oscillations generated 15~kHz elastic waves, which we detected using a high-speed camera coupled to a standard bright-field microscope. Noise correlation elastography enabled the measurement of average and local shear-wave velocities within single cells. Our results demonstrate that this method is robust and reproducible across multiple cells from the same cell line, paving the way for real-time, label-free mechanical monitoring of single cells during fast biological processes. + oai:arXiv.org:2512.18294v1 physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Ramalakshmi K, Sasmita Dash, Srilali Siragam + Gabrielle Laloy-Borgna, Maxime Fauconnier, Sibylle Gr\'egoire, Stefan Catheline, Claude Inserra - Design Guidelines for Plasmon-Enhanced CsSn$_x$Ge$_{1-x}$I$_3$ Perovskite LEDs: A DFT-Informed FDTD Study - https://arxiv.org/abs/2512.17467 - arXiv:2512.17467v1 Announce Type: new -Abstract: CsSn$_x$Ge$_{1-x}$I$_3$ as lead-free perovskites are promising for next generation NIR emitting perovskite LEDs due to their tunable bandgaps and stability. However, they suffer from poor light extraction efficiency, and accurate composition-specific optical data for these materials remain scarce. This study presents a DFT-FDTD framework to optimize light extraction via compositional tuning and plasmonic enhancement. First, DFT calculations were performed to obtain composition-specific complex refractive index and extinction coefficient values for $x = 0, 0.25, 0.5, 0.75$, and $1$. Results show bandgap increased from 1.331 eV for CsSnI$_3$ to 1.927 eV for CsGeI$_3$ with increasing Ge content, while refractive index ranges from 2.2 to 2.6 across compositions. These optical constants were then used as inputs for FDTD simulations of a PeLED structure with optimized Au/SiO$_2$ core-shell nanorods for plasmonic enhancement. A 12.1-fold Purcell enhancement was achieved for CsSn$_{0.25}$Ge$_{0.75}$I$_3$, while light extraction efficiency reached 25% for CsSn$_{0.5}$Ge$_{0.5}$I$_3$. LEE enhancement of 36% was obtained for CsSnI$_3$, and spectral overlap between emitter and plasmon resonance reached 96% for Sn-rich compositions. Design guidelines indicate CsSn$_{0.5}$Ge$_{0.5}$I$_3$ offers optimal balance of extraction efficiency (25%), Purcell enhancement (5.3$\times$), spectral overlap (93%), and oxidation stability for wearable and flexible optoelectronic applications, while CsSn$_{0.25}$Ge$_{0.75}$I$_3$ is recommended for applications prioritizing spontaneous emission rate. - oai:arXiv.org:2512.17467v1 + Controlling Ultrafast Excitations in Germanium:The Role of Pump-Pulse Parameters and Multi-Photon Resonances + https://arxiv.org/abs/2512.18299 + arXiv:2512.18299v1 Announce Type: new +Abstract: We employ the Dynamical Projective Operatorial Approach (DPOA) to investigate the ultrafast optical excitations of germanium under intense, ultrashort pump pulses. The method has very low resource demand relative to many other available approaches and enables detailed calculation of the residual electron and hole populations induced by the pump pulse. It provides direct access to the energy distribution of excited carriers and to the total energy transferred to the system. By decomposing the response into contributions from different multi-photon resonant processes, we systematically study the dependence of excited-carrier density and absorbed energy on key pump-pulse parameters: duration, amplitude, and photon energy. Our results reveal a complex interplay between these parameters, governed by resonant Rabi-like dynamics and competition between different multi-photon absorption channels. For the studied germanium setup, we find that two-photon processes are generally dominant, while one- and three-photon channels become significant under specific conditions of pump-pulse frequency, duration, and intensity. This comprehensive analysis offers practical insights for optimizing ultrafast optical control in semiconductors by targeting specific multi-photon pathways. + oai:arXiv.org:2512.18299v1 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + cond-mat.mtrl-sci + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Shoumik Debnath, Sudipta Saha, Khondokar Zahin, Ying Yin Tsui, Md. Zahurul Islam + Amir Eskandari-asl (Dipartimento di Fisica 'E.R. Caianiello', Universit\`a degli Studi di Salerno, I-84084 Fisciano), Adolfo Avella (Dipartimento di Fisica 'E.R. Caianiello', Universit\`a degli Studi di Salerno, I-84084 Fisciano) - Transient and periodic shear wave propagation in a solid-fluid coupled system - https://arxiv.org/abs/2512.17475 - arXiv:2512.17475v1 Announce Type: new -Abstract: A coupled system composed of a Newtonian fluid located on a sinusoidally-forced elastic solid is studied analytically and numerically. The focus is on the transient evolution from the beginning of the forced oscillations and on the periodic behaviour established once the transient has vanished. The analytical solution is expressed as series summations that elucidate the propagation and reflections of elastic transverse waves through the solid layer and the viscous dissipation of oscillations in the fluid layer. Short-term transients in both the fluid and the solid form at every interaction between an elastic wave and a solid boundary. The long-term transient, quantified by the power balance in the fluid layer, instead pertains to the formation of all the elastic waves in the solid layer. The system can be viewed as a generalised transient Stokes layer generated by the elastic waves or as a damped resonant oscillator when the velocity at the fluid-solid interface increases significantly with respect to the amplitude. A parametric study is carried out for three applications of technological interest, i.e. the indirect measurement of fluid viscosity, the turbulent drag reduction by travelling shear waves and the sensing and manipulation of biological flows. - oai:arXiv.org:2512.17475v1 - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Modeling and Experiments of an Injection-Locked Magnetron With Various Load Reflection Levels + https://arxiv.org/abs/2512.18304 + arXiv:2512.18304v1 Announce Type: new +Abstract: In this article, we investigate the performance of an injection-locked 5.8-GHz continuous-wave magnetron with various load reflection levels. The load reflection is introduced to an equivalent magnetron model to theoretically evaluate the system performance. The effects of different load reflection levels on the magnetron's output are numerically analyzed. Experiments are performed while the load reflection is varied using an E-H tuner between a magnetron and a circulator. A narrower locking bandwidth is observed under constant injection power with increasing load reflection. The proper-mismatched system suppresses its sideband energy, thereby reducing phase noise. The experimental features qualitatively validate the theoretical analyses results. The investigation results also provide guidance for advanced applications in communication and high-energy physics based on injection-locked magnetrons. + oai:arXiv.org:2512.18304v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Aaron D'Cruz, Pierre Ricco + 10.1109/TED.2020.3009901 + IEEE Transactions on Electron Devices, vol. 67, no. 9, pp. 3802-3808, Sept. 2020 + Xiaojie Chen, Bo Yang, Naoki Shinohara, Changjun Liu - Towards Halbach Spheres -- Icosahedral Symmetry Is Not Just Cool Anymore - https://arxiv.org/abs/2512.17497 - arXiv:2512.17497v1 Announce Type: new -Abstract: Halbach spheres provide a theoretically elegant means of generating highly homogeneous magnetic fields, but practical implementation is hindered by challenging fabrication and restricted interior access. This study examines discrete spherical Halbach configurations assembled from permanent magnets placed at the vertices of Platonic and Archimedean solids. Analytical calculations, numerical field simulations, and experimental measurements indicate that polyhedra with icosahedral symmetry achieve the most favorable balance among field strength, homogeneity, and interior accessibility. They produce exceptionally flat fourth-order central saddle points, resulting in a usable homogeneous field volume up to a factor of 260 larger than that of traditional Halbach disk or cylindrical arrays. Several magnet assemblies composed of cubical NdFeB magnets are fabricated and their three dimensional field distributions characterized, demonstrating homogeneous regions of up to several cubic centimeters with deviations below 1%. The findings establish discrete icosahedrally symmetric magnet arrays as practical, scalable building blocks for compact, highly homogeneous magnetic field sources suited to mobile magnetic resonance, and magnetophoretic applications. - oai:arXiv.org:2512.17497v1 - physics.ins-det - cond-mat.mtrl-sci - Mon, 22 Dec 2025 00:00:00 -0500 + Deterministic Reconstruction of Tennis Serve Mechanics: From Aerodynamic Constraints to Internal Torques via Rigid-Body Dynamics + https://arxiv.org/abs/2512.18320 + arXiv:2512.18320v1 Announce Type: new +Abstract: Most conventional studies on tennis serve biomechanics rely on phenomenological observations comparing professional and amateur players or, more recently, on AI-driven statistical analyses of motion data. While effective at describing \textit{what} elite players do, these approaches often fail to explain \textit{why} such motions are physically necessary from a mechanistic perspective. This paper proposes a deterministic, physics-based approach to the tennis serve using a 12-degree-of-freedom multi-segment model of the human upper body. Rather than fitting the model to motion capture data, we solve the inverse kinematics problem via trajectory optimization to rigorously satisfy the aerodynamic boundary conditions required for Flat, Slice, and Kick serves. We subsequently perform an inverse dynamics analysis based on the Principle of Virtual Power to compute the net joint torques. The simulation results reveal that while the kinematic trajectories for different serves may share visual similarities, the underlying kinetic profiles differ drastically. A critical finding is that joints exhibiting minimal angular displacement (kinematically ``quiet'' phases), particularly at the wrist, require substantial and highly time-varying torques to counteract gravitational loading and dynamic coupling effects. By elucidating the dissociation between visible kinematics and internal kinetics, this study provides a first-principles framework for understanding the mechanics of the tennis serve, moving beyond simple imitation of elite techniques. + oai:arXiv.org:2512.18320v1 + physics.app-ph + cs.RO + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Ingo Rehberg, Peter Bl\"umler + Sun-Hyun Youn - H-mode transition in the TJ-II stellarator plasmas - https://arxiv.org/abs/2512.17522 - arXiv:2512.17522v1 Announce Type: new -Abstract: Since the first H-mode transitions were observed in TJ-II plasmas in 2008, an extensive experimental effort has been done aiming a better physics understanding of confinement transitions. In this paper, an overview of the main findings related to the L-H transition in TJ-II is presented including how the radial electric field is driven, which are the possible mechanisms for turbulence suppression, and what are the related temporal and spatial scales which can impact the transition. The trigger of the L-H transition in TJ-II plasmas is found to be more correlated with the development of fluctuating $E\times B$ flows than with steady-state $E_r$ effects, pointing to the role played by zonal flows in mediating the transition. Experimental evidence supporting the predator-prey relationship between turbulence and flows as the basis for the L-H transition, found for the first time in TJ-II, reinforces this conclusion. Besides, the reduction in the turbulent transport at the transition is detected at the barrier region but also in a wider radial range with weak or even zero $E\times B$ flow shear, what points to other mechanisms beyond the turbulence suppression by local sheared flows. - oai:arXiv.org:2512.17522v1 - physics.plasm-ph - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1098/rsta.2021.0229 - Phil. Trans. R. Soc. A 381: 20210229 (2023) - T. Estrada, C. Hidalgo - - - HydroGym: A Reinforcement Learning Platform for Fluid Dynamics - https://arxiv.org/abs/2512.17534 - arXiv:2512.17534v1 Announce Type: new -Abstract: Modeling and controlling fluid flows is critical for several fields of science and engineering, including transportation, energy, and medicine. Effective flow control can lead to, e.g., lift increase, drag reduction, mixing enhancement, and noise reduction. However, controlling a fluid faces several significant challenges, including high-dimensional, nonlinear, and multiscale interactions in space and time. Reinforcement learning (RL) has recently shown great success in complex domains, such as robotics and protein folding, but its application to flow control is hindered by a lack of standardized benchmark platforms and the computational demands of fluid simulations. To address these challenges, we introduce HydroGym, a solver-independent RL platform for flow control research. HydroGym integrates sophisticated flow control benchmarks, scalable runtime infrastructure, and state-of-the-art RL algorithms. Our platform includes 42 validated environments spanning from canonical laminar flows to complex three-dimensional turbulent scenarios, validated over a wide range of Reynolds numbers. We provide non-differentiable solvers for traditional RL and differentiable solvers that dramatically improve sample efficiency through gradient-enhanced optimization. Comprehensive evaluation reveals that RL agents consistently discover robust control principles across configurations, such as boundary layer manipulation, acoustic feedback disruption, and wake reorganization. Transfer learning studies demonstrate that controllers learned at one Reynolds number or geometry adapt efficiently to new conditions, requiring approximately 50% fewer training episodes. The HydroGym platform is highly extensible and scalable, providing a framework for researchers in fluid dynamics, machine learning, and control to add environments, surrogate models, and control algorithms to advance science and technology. - oai:arXiv.org:2512.17534v1 + Geometric Rectification of Surface Activity Induced Flow in Confined Channels + https://arxiv.org/abs/2512.18351 + arXiv:2512.18351v1 Announce Type: new +Abstract: Conventional pressure-driven flow obeys Poiseuille's law, with the mean velocity scaling as $u \propto r^2$ under confinement. Here we identify a distinct transport mode driven by spatially structured surface activity (e.g., mass exchange or boundary slip gradients), which is rectified by geometric asymmetry into a net axial flux. Using a minimal exchange model, we show that this mechanism exhibits four defining signatures that are inconsistent with classical lubrication theory: (i) an inverted confinement scaling $u \propto r^{-1}$ (``narrower-is-faster''); (ii) leading-order viscosity independence; (iii) macroscopic length amplification ($Q \propto L$); and (iv) linear superposition with pressure-driven flows. These results establish confined channels as active geometric rectifiers and provide a unified framework for surface-induced transport from microfluidic to biological settings. + oai:arXiv.org:2512.18351v1 physics.flu-dyn - cs.AI - cs.LG - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Christian Lagemann, Sajeda Mokbel, Miro Gondrum, Mario R\"uttgers, Jared Callaham, Ludger Paehler, Samuel Ahnert, Nicholas Zolman, Kai Lagemann, Nikolaus Adams, Matthias Meinke, Wolfgang Schr\"oder, Jean-Christophe Loiseau, Esther Lagemann, Steven L. Brunton - - - Fully stabilized 25 GHz frequency comb for frequency calibration of optical spectrum analyzer - https://arxiv.org/abs/2512.17536 - arXiv:2512.17536v1 Announce Type: new -Abstract: Optical spectrometers are widely used in scientific and industrial applications, and precise frequency calibration is essential for ensuring their reliable performance. Traditionally, spectrometers have been calibrated using reference gas cells or reference lamps. However, such conventional methods are not enough to meet the demands for high accuracy and stability. Although frequency-stabilized lasers offer excellent frequency uncertainty, they provide only a single calibration point at a fixed frequency, which is unsuitable for wide-range spectrometer calibration. In this work, we demonstrate a fully stabilized, high-repetition rate electro-optic frequency comb (EO comb) as an absolute frequency reference providing multiple calibration points over a broad spectral range. Our 25 GHz EO comb provides a broadband spectrum spanning from 189.5 THz to 196 THz (corresponding to 1530 nm to 1582 nm), traceable to a frequency standard with a relative standard uncertainty of 10^-13. The well-defined and evenly spaced comb modes can be spectrally resolved by conventional optical spectrometers, enabling wide-range, high-precision frequency calibration. We directly calibrated a commercial spectrometer by referencing its measured frequency values to our well-defined comb modes, thereby evaluating the frequency error with a standard uncertainty of 20 MHz (or relative standard uncertainty of 10^-7), which is limited by the Type A uncertainty (repeatability) of the spectrometer. The proposed method is simple to implement and provides multiple calibration points referenced to the frequency standards over a broad spectral range. This approach improves both the calibration and performance evaluation of spectrometers, and it contributes to the advancement of optical metrology. - oai:arXiv.org:2512.17536v1 - physics.optics - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yoonkwon On, Dae Hee Kim, Sujin Kim, Yong Jin Kim, Jong-Ahn Kim, Sunghoon Eom, Jae Yong Lee, Yoon-Soo Jang + Zheng Li - Enhanced and directional light emission from two-dimensional excitons using Mie voids - https://arxiv.org/abs/2512.17546 - arXiv:2512.17546v1 Announce Type: new -Abstract: Controlling light emission at the nanoscale has important applications in solid-state lighting, displays, and quantum light sources. Achieving this control requires both enhanced local electromagnetic fields to boost emission intensity and engineered radiation patterns to direct photons efficiently. Mie voids, consisting of an air cavity surrounded by a high-index semiconductor, are particularly suited for this purpose because they expose their strongest fields in an accessible region for nearby emitters while supporting resonances that shape directional emission through interference. Here, we demonstrate an all-van der Waals nanophotonic platform that couples excitons in atomically thin WS$_2$ to Mie void resonators formed in WSe$_2$. Guided by electromagnetic simulations, we identify void geometries that maximize photoluminescence through synergistic enhancement of excitation and emission processes. We also develop a two-step fabrication strategy that enables independent control of void diameter and depth, providing a route to systematically tune the optical response. Experimentally, we observe up to a 600-fold increase in photoluminescence intensity from monolayer WS$_2$ placed on individual voids compared to on an unstructured WSe$_2$, along with pronounced out-of-plane beaming of light that yields a forward-to-off-axis enhancement of 2.6 dB. Our results establish Mie voids in van der Waals semiconductors as a new platform for controlling light-matter interactions and realizing compact, directional, and efficient nanoscale light sources. - oai:arXiv.org:2512.17546v1 - physics.optics + Discrete Electron Emission + https://arxiv.org/abs/2512.18355 + arXiv:2512.18355v1 Announce Type: new +Abstract: Analysis of space-charge effects on electron emission typically makes some assumption of continuity and smoothness, whether this is continuity of charge as in the classical derivation of the Child-Langmuir current, or the mean-field approximation used in particle-in-cell simulations. However, when studying the physics of electron emission and propagation at the mesoscale it becomes necessary to consider the discrete nature of electronic charge to account for the space-charge effect of each individual point charge. In this paper we give an extensive analysis of some previous work on the distribution of electrons under space-charge limited conditions. We examine the spacing of electrons as they are emitted from a planar surface, We present simplified models for analysis of such conditions to derive scaling laws for emission and compare them to computer simulations. + oai:arXiv.org:2512.18355v1 + physics.acc-ph cond-mat.mes-hall - Mon, 22 Dec 2025 00:00:00 -0500 - new - http://creativecommons.org/licenses/by/4.0/ - Avishek Sarbajna, Ganesh Ghimire, Ilia Breev, Xavier Zambrana-Puyalto, Cheng Xiang, Alexander Huck, Timothy J. Booth, S{\o}ren Raza - - - Guided progressive reconstructive imaging: a new quantization-based framework for low-dose, high-throughput and real-time analytical ptychography - https://arxiv.org/abs/2512.17561 - arXiv:2512.17561v1 Announce Type: new -Abstract: By profiting from recent developments in detector technologies, making it possible to access a stream of detection events with few-ns time resolutions, a new ptychographic workflow is established. This methodological framework, referred to as guided progressive reconstructive imaging, relies on a quantization-based description of the acquired intensity, through an elementary derivation. Established direct phase retrieval solutions, such as the Wigner distribution deconvolution approach, can then be adapted to a continuous treatment of received counts, with no need for a dense data representation. Consequently, the result is obtained in the form of a progressively improving estimate, while providing immediate user feedback thanks to a remarkable processing speed, able to surpass the acquisition bandwidth. This fast measurement is enabled by the cumulative usage of a pre-calculated library of kernel-limited guide functions, compiling count-wise contributions as a function of the triggered detector pixel. Hence, the reconstruction offers the same advantages of direct phase retrieval methods, in particular a high dose-efficiency and the absence of complex convergence dynamics, with much less stringent restrictions on the field of view than is typical in current alternatives. Its implementation is also significantly more straightforward and flexible. Overall, this work constitutes a major evolution in the state-of-the-art, facilitating repeatable and low-dose experiments with high accessibility, and being applicable to electron-based imaging, X-ray diffraction and optical microscopy. - oai:arXiv.org:2512.17561v1 - physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hoelen L. Lalandec Robert, Arno Annys, Tamazouzt Chennit, Jo Verbeeck + Arnar Jonsson, Kristinn Torfason, Andrei Manolescu, Agust Valfells - The resonance behavior of a bubble near a boundary - https://arxiv.org/abs/2512.17575 - arXiv:2512.17575v1 Announce Type: new -Abstract: We present an analytical model for the frequency response of a gas microbubble oscillating near a spherical inclusion of arbitrary size and mechanical nature (rigid, fluid, or viscoelastic) immersed in a viscous compressible fluid. The model considers both radial and nonspherical oscillations in the linear regime and predicts how their resonance frequencies and oscillation amplitudes are altered by the bubble size, material properties, and distance to the nearby sphere. As a key application, we demonstrate that scanning the frequency response of a bubble near a viscoelastic object, such as an erythrocyte-like particle mimicking a biological cell, offers a way to recover its mechanical properties through inverse modeling, opening new possibilities for high-resolution elastography at the microscale. - oai:arXiv.org:2512.17575v1 + Nondiffusive transport of inertial heavy impurities in drift-wave turbulence + https://arxiv.org/abs/2512.18394 + arXiv:2512.18394v1 Announce Type: new +Abstract: We investigate the transport behavior of tungsten impurities with finite inertia in drift-wave turbulence using the Hasegawa-Wakatani model. Unlike previous tracer-based models, our simulations reveal a transition to non-diffusive dynamics for a range of charge states. This novel mechanism offers a turbulence-driven route to core impurity accumulation. This finding underscores the nontrivial role of particle inertia in impurity dynamics and has strong implications for impurity control in future fusion devices. + oai:arXiv.org:2512.18394v1 + physics.plasm-ph physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Thomas Micol, Alexander A. Doinikov, Cyril Mauger, Claude Inserra + 10.1103/4px7-2vtt + Zetao Lin, Benjamin Kadoch, Sadruddin Benkadda, Kai Schneider - A generalized perturbative approach for the computation of nonlinear scattering problems - https://arxiv.org/abs/2512.17608 - arXiv:2512.17608v1 Announce Type: new -Abstract: We present a perturbative technique for modeling the scattering of light by a nonlinear material. This approach eliminates the need for an iterative algorithm to solve the fully coupled nonlinear problem. We demonstrate its effectiveness in the cases of a nonlinear anisotropic slab and a nonlinear periodic crystal, both illuminated by a plane wave under conical incidence and arbitrary polarization. Quantitative comparisons of the accuracy and computational time with a previously published rigorous model are provided. - oai:arXiv.org:2512.17608v1 - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + Relations Among Different Inequality Measures in Complex Systems: From Kinetic Exchange to Earthquake Models + https://arxiv.org/abs/2512.18408 + arXiv:2512.18408v1 Announce Type: new +Abstract: We present a numerical study of several inequality measures across two kinetic wealth-exchange models with extreme inequality features (namely the Banerjee model, and the Chakraborti or Yard-Sale model) and two earthquake simulating models (namely the Chakrabarti-Stinchcombe two-fractal overlap model and the nonlinear dynamical Burridge-Knopoff model), and a synthetic Pareto distribution. For each model we compute numerically the Lorenz function for the respective models' wealth, overlap magnitude or avalanche distributions. We then estimate the variations of Gini (g), Pietra (p) and Kolkata (k) indices in these models with systematic variations of saving propensity (for the two wealth-exchange models), with systematic variations of generation or block numbers (for the two earthquake simulating models). We find, the values of p/(2k-1) (across the wealth exchange models and the two-fractal overlap model) remain a little above unity (theoretically predicted value) and deviating a little higher by a maximum of 4% near g = k nearly equal to 0.86, which was identified earlier to be the precursor point of criticality in several self-organized critical models (k = 0.80 corresponds to Pareto's 80-20 law). In the Burridge-Knopoff model for some instances of time, the value of p/(2k-1) drops a little below unity. This and some other quantitatively similar behaviors of the inequality indices across socio-economic and geophysical models may provide a coherent and comparative framework for identifying the subtle features in the statistics of such disparate dynamical systems. + oai:arXiv.org:2512.18408v1 + physics.soc-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - J\'er\'emy Itier, Gilles Renversez, Fr\'ed\'eric Zolla + Shohini Sen, Suchismita Banerjee, Bikas K Chakrabarti - Fast, systematic and robust relative binding free energies for simple and complex transformations : dual-LAO - https://arxiv.org/abs/2512.17624 - arXiv:2512.17624v1 Announce Type: new -Abstract: Relative Binding Free Energy (RBFE) calculations are a cornerstone of rational hit-to-lead and lead optimization in modern drug discovery. However, the high computational cost and limited reliability in tackling large or complex molecular transformations often prevent their routine, high-throughput use. Here we introduce dual-LAO, a novel, highly efficient method for calculating RBFE. Building on the Lambda-ABF-OPES framework, this method combines a dual-topology setup and suitable restraints to dramatically accelerate free energy convergence. We demonstrate that dual-LAO, in combination with the AMOEBA polarizable force field, achieves an unprecedented acceleration factor of 15 to 30 times compared to current state-of-the-art methods on standard drug targets. Crucially, the approach maintains high accuracy and successfully tackles previously prohibitive molecular changes, including scaffold-hopping, buried water displacement, charge changes, ring-opening, and binding pose perturbations. This significant leap in efficiency allows for the widespread, routine integration of predictive molecular simulations into the rapid optimization cycles of drug discovery, enabling chemists to confidently model historically challenging systems in timescales compatible with real-world project deadlines. - oai:arXiv.org:2512.17624v1 - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Life as Non-Normal Chemical Accelerator + https://arxiv.org/abs/2512.18438 + arXiv:2512.18438v1 Announce Type: new +Abstract: Life is commonly described as a self-organized, far-from-equilibrium process that maintains internal order by consuming free energy and exporting entropy. This thermodynamic view underlies diverse theoretical frameworks -- from autopoiesis and relational biology to autocatalytic sets and hypercycles -- yet dissipation is typically treated as a necessary consequence of living organization rather than as a property shaped by its internal dynamics. Here, through explicit calculations of biotic chemical reactions and empirical documentation, we show that living systems universally function as non-normal chemical accelerators. Their elevated entropy production emerges from the asymmetric and hierarchical architecture of their biochemical networks. We introduce a general conceptual and mathematical framework in which biological structuration is understood as a dynamical property. Characterized by asymmetric couplings and transient amplification despite asymptotic stability, non-normal dynamics are shown to naturally generate kinetic acceleration, enhanced energy throughput, and phase-transition-like reorganizations without classical bifurcations. In this view, biological organization is not merely compatible with dissipation but actively structured to amplify free-energy flux and entropy export. We support this perspective with empirical and theoretical evidence that biochemical networks generically give rise to intrinsically non-normal operators through non-reciprocal interactions and hierarchical design. This framework yields testable predictions for dissipation rates, robustness, and evolutionary design principles, and suggests a kinetic principle of evolution in which living systems preferentially construct increasingly non-normal reaction architectures, driving sustained amplification of chemical fluxes and entropy flow. + oai:arXiv.org:2512.18438v1 + physics.bio-ph + q-bio.OT + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Narjes Ansari, F\'elix Aviat, J\'er\^ome H\'enin, Jean-Philip Piquemal, Louis Lagard\`ere + http://creativecommons.org/licenses/by/4.0/ + Didier Sornette, Virgile Troude - Simulating vacuum birefringence with a diffractive beam propagation code - https://arxiv.org/abs/2512.17641 - arXiv:2512.17641v1 Announce Type: new -Abstract: Ninety years after their prediction, quantum vacuum nonlinearities in macroscopic electromagnetic fields still await a direct experimental verification in the laboratory. A particularly promising route towards their first measurement is the collision of counter-propagating laser beams in a pump-probe type experiment. Here, the key challenge is to separate the small quantum vacuum signal at the oscillation frequency of the probe that is mainly emitted in the vicinity of its forward cone from the large probe background. While quantitatively accurate predictions of the associated quantum vacuum signals are available, to date there is no framework that combines these predictions with a diffractive beam propagation code. Such codes are designed to holistically model optical experiments and can reliably account for diffraction and absorption losses of optical devices, like lenses and apertures. The latter inevitably influence and modify both the induced signal and background components prior to their detection in experiment. The present work addresses this topical issue and reports on the first implementation of a quantum vacuum signals emission module in an established diffractive beam propagation toolkit designed for the realistic modelling of optical experiments. - oai:arXiv.org:2512.17641v1 - physics.optics - hep-ph - Mon, 22 Dec 2025 00:00:00 -0500 + A Toy Model of the Madden-Julian Oscillation + https://arxiv.org/abs/2512.18443 + arXiv:2512.18443v1 Announce Type: new +Abstract: We discuss a simple three layer model of the tropical atmosphere. The rainfall variance of the model is dominated by a rainfall mode moving parallel to the equator having the approximate size and propagation speed of the Madden-Julian Oscillation (MJO). The origin of the convective aggregation in the model is the imposition of distinct length scales for the deep updraft and stratiform downdraft circulations. Subsidence induced by the deep updraft circulation suppresses convective instability on a scale of $\sim$ 1000 km, while ascent induced by the downdraft circulation promotes convective instability on a scale of $\sim$ 500 km. Within the MJO envelope, high rainfall rates are maintained both by increased column relative humidity, and increased variance in lower tropospheric vertical motion. Each of the three model layers has a prescribed target pressure thickness. Convective mass fluxes introduce a mass excess into grid cells where there is net detrainment, and a mass deficit into grid cells from which there is net entrainment. Horizontal transport in the model is based on export of mass from grid cells where there is an excess, and import of mass toward grid cells where there is a deficit. The resulting patterns of horizontal convergence and divergence generate vertical motions between model levels. The simulated MJO events propagate eastward when there is a slight preference for mass deficits in the boundary layer to be compensated by inward flow from the west. The forward propagation of the MJO is limited by the rate at which the downdraft circulation within the MJO is able to generate net upward motion and promote new convective activity in advance of the leading edge. We also offer some guidance on how convective parameterizations that are implemented in models with more realistic dynamical schemes might be designed to exhibit stronger MJO variance. + oai:arXiv.org:2512.18443v1 + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Aim\'e Matheron, Michal \v{S}m\'id, Matt Zepf, Felix Karbstein + Ian Folkins - High-purity amplification of circularly polarized orbital angular momentum modes in an active spun ring-core tapered fiber - https://arxiv.org/abs/2512.17645 - arXiv:2512.17645v1 Announce Type: new -Abstract: Structured light, optical fields engineered in their spatial, polarization, or phase degrees of freedom, has become a key resource across advanced communication, sensing, imaging, and quantum technologies. Optical fibers nowadays play an essential role in this landscape, providing stable and scalable platforms for guiding, and amplifying complex modes such as vector and orbital angular momentum (OAM) beams. In this work, we demonstrate an active spun ring-shaped tapered fiber as a gain medium for efficient amplification of OAM modes preserving their modal purity and polarization topology. OAM beams with topological charges l = 1 and l = 2 carrying 60 ps pulses at 15 MHz repetition rate at 1030 nm wavelength are amplified over 1.2 W average power with modal purity over 95%. The spatially resolved measurement of the OAM beam polarization topology revealed small distortion due to the coupling in to neighbour modes. These results demonstrate the high potential of active spun ring-shaped tapered fibers for power scaling of complex beams, preserving their phase and polarization structure simultaneously. - oai:arXiv.org:2512.17645v1 - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + An energetically and thermodynamically consistent Boussinesq model + https://arxiv.org/abs/2512.18461 + arXiv:2512.18461v1 Announce Type: new +Abstract: The Boussinesq approximation is a cornerstone of geophysical fluid dynamics, yet its thermodynamic and energetic underpinnings have remained ambiguous. In standard formulations, the links with the fully compressible Navier--Stokes equations are obscured, internal energy is only implicit, and the representation of diffusion and irreversibility remains \textit{ad hoc}. Here we derive a new Boussinesq model in a fully traceable way from the two-component compressible Navier-Stokes equations, ensuring exact energy conservation and consistent thermodynamics. Assuming a linear equation of state, our model treats density as a proxy for specific volume, distinguishes in-situ and potential temperature explicitly, and incorporates diffusive fluxes that homogenise the correct thermodynamic potentials, ensuring consistent non-negative entropy production. The result clarifies the status of gravitational potential energy, resolves ambiguities surrounding salinity--entropy coupling, and retains the small terms carriers of key information about thermodynamics. Alongside this, we introduce an exact thermodynamically soundproof (TS) model whose weak diabatic divergence highlights the role of compressibility effects in stratified turbulence. Together, these models provide a transparent framework that reconciles classical approximations with compressible energetics, offering better-defined pathways for analysing stratified mixing, mixing efficiency, and the energy budgets of geophysical flows. + oai:arXiv.org:2512.18461v1 + physics.flu-dyn + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Iuliia Zalesskaia, Hassan Asgharzadeh B., Zahra Eslami, Hossein Fathi, Evgenii Gribanov, Andrey Grishchenko, Florian Lindner, Katrin Wondraczek, Evgeny Savelyev, Marco Ornigotti, Valery Filippov, Regina Gumenyuk + http://creativecommons.org/licenses/by/4.0/ + R. Tailleux, T. Dubos, B. J. Hatton - Hyperbolic-enhanced Raman scattering in van der Waals MoOCl2: from Fano resonances to picomolar detection - https://arxiv.org/abs/2512.17647 - arXiv:2512.17647v1 Announce Type: new -Abstract: Natural van der Waals (vdW) crystals with hyperbolic dispersion challenge artificial metamaterials but remain confined to the mid-infrared spectrum. The emergence of MoOCl2, a quasi-one-dimensional metal with in-plane hyperbolicity, overcomes this spectral limit, shifting the focus to the practical visible range. Here, utilizing angle-resolved Raman spectroscopy, we uncover a highly anisotropic vibrational response characterized by pronounced Fano resonances and polarization switching, which serve as signatures of strong coupling between phonons and the metallic continuum. Harnessing this interaction, we demonstrate "Hyperbolic-Enhanced Raman" (HypER) scattering, where MoOCl2 provides polarization-tunable enhancement factors exceeding 10^7 and picomolar-level detection down to 100 pM, without any nanostructuring. These results establish MoOCl2 as a simple, air-stable, wafer-compatible platform for visible-range hyperbolic nanophotonics and lithography-free sensing. - oai:arXiv.org:2512.17647v1 + Microscale selective laser sintering of Cu nanoparticles with a short-wavelength nanosecond laser + https://arxiv.org/abs/2512.18465 + arXiv:2512.18465v1 Announce Type: new +Abstract: Microscale additive manufacturing of reflective copper is becoming increasingly important for microelectronics and microcomputers, due to its excellent electrical and thermal conductivity. Yet, it remains challenging for state-of-the-art commercial metal 3D printers to achieve sub-100-micron manufacturing. Two aspects are sub-optimal using commercial laser powder bed fusion systems with infrared (IR) lasers (wavelength of 1060-1070 nm): (1) IR laser has a low absorption rate for Cu, which is energy-inefficient for manufacturing; (2) short wavelength lasers can potentially offer higher resolution processing due to the diffraction-limited processing. On the other hand, laser sintering or melting typically uses continuous wave (CW) lasers, which may reduce the manufacturing resolution due to a large heat-affected zone. Based on these facts, this study investigates the UV (wavelength of 355 nm) nanosecond (ns) laser sintering of Cu nanoparticles. Different laser processing parameters, as well as different nanoparticle packing densities, are studied. Our results show that a short-wavelength laser can reduce the required energy for sintering with decent morphology, and a densified nanoparticle powder bed favors continuous melting. We further show that sub-20 micron printing can be readily achieved with a UV ns laser. These findings provide new insights into short-wavelength laser-metal nanoparticle interactions, which may pave the way to achieve high-resolution micro and nano-scale additive manufacturing. + oai:arXiv.org:2512.18465v1 physics.optics - cond-mat.mes-hall cond-mat.mtrl-sci - physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Anton Minnekhanov, Gleb Tikhonowski, Georgy Ermolaev, Konstantin V. Kravtsov, Gleb Tselikov, Adilet Toksumakov, Aleksandr Slavich, Ivan Kazantsev, Andrey Vyshnevyy, Ivan Kruglov, Ilya Radko, Zdenek Sofer, Aleksey Arsenin, Kostya S. Novoselov, Valentyn Volkov + Youwen Liang, Bo Shen, Wan Shou - $\Lambda$-Enhanced Gray Molasses Cooling of $^{85}$Rb Atoms in Tweezers Using the D$_2$ Line - https://arxiv.org/abs/2512.17653 - arXiv:2512.17653v1 Announce Type: new -Abstract: We demonstrate the implementation of $\Lambda$-enhanced gray molasses cooling on the D$_2$ line of $^{85}$Rb atoms in an optical tweezer array. This technique yields lower atomic temperatures of 4.0(2) $\mu$K compared to red-detuned polarization gradient cooling, and consequently extends the $T_2^*$ coherence time of the hyperfine clock qubit by a factor of 1.5. The method is alignment-free and can be readily implemented on laser beams used for magneto-optical trapping, as it only requires frequency and phase modulation control. Our experimental observations are corroborated by a numerical model based on a semi-classical force approach extended to a four-level system, including two hyperfine states of the upper manifold that are 120 MHz apart. - oai:arXiv.org:2512.17653v1 + Lineshape-asymmetry-caused shift in atomic interferometers + https://arxiv.org/abs/2512.18476 + arXiv:2512.18476v1 Announce Type: new +Abstract: We investigate the shift caused by asymmetry of spectroscopic lineshape in atomic interferometers, which has not previously been discussed in the scientific literature. This asymmetry arises because laser field is frequency-chirped not only during the free-evolution intervals of atoms, but also during the Ramsey pulses. As a result, the effective detuning from the working atomic transition during the pulses also depends on the chirping rate, which, in turn, leads to the lineshape-asymmetry-caused shift (LACS). It is shown that this shift has an inverse cubic dependence of $\propto 1/T^3$ on the duration of the interval between the Ramsey pulses $T$, which markedly contrasts with the $\propto 1/T^2$ dependence typical in atomic interferometry. Therefore, the metrological importance of this shift substantially increases for compact atomic interferometers with a short baseline. For example, for interferometers-gravimeters using two-photon transitions in rubidium atoms, at $T\sim 1$~ms we estimate the LACS shift and its variations at the level of 0.1-1~mGal, while for $T\sim 100$~$\mu$s this can reach a value of 0.1-1~Gal. + oai:arXiv.org:2512.18476v1 physics.atom-ph - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-sa/4.0/ - Deon Janse van Rensburg, Rogier Venderbosch, Yuri van der Werf, Jesus del Pozo Mellado, Marijn Venderbosch, Rianne Lous, Edgar Vredenbregt, Servaas Kokkelmans + http://creativecommons.org/licenses/by/4.0/ + V. I. Yudin, O. N. Prudnikov, A. V. Taichenachev, M. Yu. Basalaev, D. N. Kapusta, A. N. Goncharov, M. D. Radchenko, V. G. Pal'chikov, L. Zhou, M. S. Zhan - Statistical field theory for dialectology - https://arxiv.org/abs/2512.17668 - arXiv:2512.17668v1 Announce Type: new -Abstract: Is it possible to develop a `physics of language' which can explain the spatial, temporal and social patterns we see, and which can predict future change like we forecast the weather? Such a theory is likely to involve ideas from statistical physics. A substantial literature already applies these ideas to language. However, we lack a model which can match the spatial-temporal detail of historical changes at the level of individual linguistic features, and which offers a principled mechanism to predict the future. Here we present a statistical field theory for the evolution of linguistic variables which takes steps to fill this gap. Linguistic variant frequencies are represented as a stochastic state field with spatial interaction and social conformity, coupled to a latent bias field with Onsager Machlup action that reduces overfitting to data. We derive parameter inference procedures and demonstrate them using examples of large-scale dialect survey data from the twentieth century United States. The bias field has a characteristic half-life, which determines the horizon over which linguistic change can be predicted. Inferred model parameters provide evidence for surface-tension-driven coarsening of dialect regions, with population-density gradients exerting systematic forces on interfaces. - oai:arXiv.org:2512.17668v1 - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Suborbital Characterization of Atmospheric Profiles and Cosmic Radiation over the Mexican Plateau + https://arxiv.org/abs/2512.18510 + arXiv:2512.18510v1 Announce Type: new +Abstract: We report suborbital in situ measurements of atmospheric thermodynamic variables and ionizing cosmic radiation obtained during a stratospheric balloon experiment conducted over the Mexican Plateau. The flight reached a maximum geometric altitude of 28.94 km above mean sea level, providing vertical sampling of the troposphere, tropopause, and lower stratosphere. Continuous temperature and pressure measurements acquired during ascent and descent were used to derive vertical profiles and to compute atmospheric density as a function of altitude under the hydrostatic approximation. The resulting thermal structure exhibits distinct lapse-rate regimes, allowing for a piecewise parametrization consistent with the International Standard Atmosphere (ISA) within the sampled altitude range. + Simultaneous measurements of ionizing radiation show the expected altitude dependence of secondary cosmic-ray fluxes generated by atmospheric cascades, including the formation of a Regener-Pfotzer maximum. A peak ambient dose equivalent rate of 2.96 microGy h^{-1} was measured at an altitude of 18.64 km, consistent with mid-latitude stratospheric conditions. To the best of our knowledge, this experiment constitutes the first documented stratospheric balloon mission conducted in the State of Mexico to combine near-space atmospheric profiling with direct in situ measurements of ionizing cosmic radiation at altitudes approaching 30 km. + oai:arXiv.org:2512.18510v1 + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - James Burridge + http://creativecommons.org/licenses/by-sa/4.0/ + U. Ochoa-Torrentera, R. A. Vazquez-Romero, J. Sumaya-Martinez - Bound States to the Continuum: Time-varying Spoof Acoustic Surface Waves - https://arxiv.org/abs/2512.17692 - arXiv:2512.17692v1 Announce Type: new -Abstract: We develop a theoretical framework for time-modulated acoustic metasurfaces comprising a line array of modulated cavities, and show that bound acoustic surface waves can undergo temporal diffraction from bound states localised at an interface into bulk waves. The dispersion relation is derived via an operator formalism that captures the spatio-temporal coupling between Floquet sidebands. We show that under periodic modulation of the cavity length sidebands spaced by the modulation frequency are produced (diffraction in time), enabling the coupling of bound surface acoustic waves with bulk radiation i.e. from a bound state \textit{to} the continuum. We observe the negative-frequency spectra as spatial reflections along the array via time-domain finite element simulations. Spectral $k$-gaps are observed at band crossings, with the width of the gap proportional to the modulation amplitude. The modulation enters solely through a time-dependent reflection phase, such that the framework applies generally to metasurfaces with programmable boundary conditions, beyond purely mechanical modulation. - oai:arXiv.org:2512.17692v1 + Enhanced diffusion in self-nanoconfined water channels between periodically modulated surfaces: insights from molecular dynamics simulations + https://arxiv.org/abs/2512.18514 + arXiv:2512.18514v1 Announce Type: new +Abstract: Water nanoconfinement is known to occur inside material void spaces, such as 2D confinement between surfaces, 1D confinement inside nanotubes, and variable-dimension confinement inside nanoporous materials. In the present work we investigate, through molecular dynamics simulations, the morphologies and self-diffusion coefficient of water channels that are nanoconfined in the void space between adjacent surfaces of nanotube bundles - an existing class of materials. In our simulations, we begin with water filling completely the void space, and then we progressively increase the inter-surface separation, maintaining the water content. We find that, as the inter-surface separation progresses, the dimensionality of the water channel decreases from 2D to 1D, the latter consisting of self-confined water channels along surface grooves. The morphologies and self-diffusion coefficients of these 1D water nanochannels are strongly dependent on the nature of the water-surface interaction and on the diameter of the nanotubes. Interestingly, as we decrease the nanotube diameter from 10 to 5 nm, the self-diffusion coefficients of the 1D channels increase by tenfold for hydrophilic surfaces and by sixfold for hydrophobic surfaces, surpassing, in both cases, the bulk water values. We also investigated the water channels at the interstitial voids of the bulk bundle material, finding 1D water channels that are similar to the surface ones. + oai:arXiv.org:2512.18514v1 physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + cond-mat.mtrl-sci + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - E. Paul, G. J. Chaplain, J. Li, T. A. Starkey, S. A. R. Horsley + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Bruno H. S. Mendon\c{c}a, Elizane E. de Moraes, H\'elio Chacham - Measuring fidelity of implementation of named active learning methods in physics - https://arxiv.org/abs/2512.17699 - arXiv:2512.17699v1 Announce Type: new -Abstract: Various active learning methods have been developed for introductory physics, and these methods are increasingly being adopted by instructors. However, instructors often do not implement these methods exactly as was originally intended by the developers, as they may face issues related to funding and institutional support for active learning and/or have different instructional contexts (e.g., student populations) and environments (e.g., physical classroom layouts) than the developers. Existing research does not sufficiently capture the range of variation in instructor implementation of established active learning methods, especially in comparison to high-fidelity implementations. In this study, we first identify the critical components (i.e., components without which the active learning method cannot be said to have been implemented) of three named active learning methods: SCALE-UP, ISLE, and Tutorials. We then evaluate the fidelity with which 18 different introductory physics instructors implement these methods by analyzing classroom observations and comparing the extent to which these broader implementations use each critical component in their classroom to high-fidelity implementations. We find across all three active learning methods that broader implementations spend similar amounts of class time on the critical components as high-fidelity implementations. At the same time, we observe substantial variation in the specific styles that broader implementers operationalize these critical components (e.g., doing a few long activities versus many short activities). Finally, we find no clear relationship between fidelity of implementation and student conceptual learning gains for our study's sample of instructors, providing preliminary evidence that different ways of implementing the critical components of active learning method may all effectively improve student understanding. - oai:arXiv.org:2512.17699v1 - physics.ed-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Unraveling the effects of atmospheric dynamics on wakes with a controlled synthetic inflow methodology + https://arxiv.org/abs/2512.18518 + arXiv:2512.18518v1 Announce Type: new +Abstract: Winds in the atmospheric boundary layer (ABL) display a wide range of velocity profiles and turbulence properties that affect wind turbine wake dynamics. However, standard concurrent-precursor large eddy simulations (LES) often neglect phenomena such as mesoscale patterns, limiting the range and controllability of inflow parameters that can be studied. Here, we propose a synthetic inflow LES method with high inflow controllability to allow parameters such as shear, turbulence, and Coriolis effects to be varied independently, facilitating the efficient exploration of wake dynamics across the full range of conditions observed in the field. The synthetic inflow method faithfully reconstructs wake dynamics when compared with standard concurrent-precursor LES. We then run a suite of over 600 LES cases to investigate the ABL processes that most affect wake dynamics. We find that wake recovery strongly depends on inflow wind veer, especially at low turbulence intensities, due to the elongation of the skewed wake. Furthermore, we identify a novel scaling relation that collapses wake deflections and dynamics onto the combination of shear and veer. The suite of LES cases elucidates ABL regimes and wake dynamics where current and future wind turbines may operate, building toward improved wake modeling for wind farm design and control. + oai:arXiv.org:2512.18518v1 + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Ibukunoluwa Bukola, Meagan Sundstrom, Justin Gambrell, Colin Green, Adrienne L. Traxler, Eric Brewe + Kirby S. Heck, Michael F. Howland - Reconstructing Pre-Satellite Tropical Cyclogenesis Climatology Using Deep Learning - https://arxiv.org/abs/2512.17711 - arXiv:2512.17711v1 Announce Type: new -Abstract: A reliable tropical cyclone (TC) climatology is the key to assessing historical and future changes in TC activities. While global TC records have been systematically maintained since the early 1940s, substantial uncertainties remain for the pre-satellite era during which TC observations relied mostly on scattered aircraft reconnaissance and sporadic ship reports. This study presents a deep learning (DL) approach to reconstruct historical TC activity in the western North Pacific (WNP) basin, with a main focus on the pre-satellite era. Using data feature enrichment tailored for tropical cyclogenesis (TCG), we demonstrate that DL can effectively capture the main characteristics and changes in TCG climatology during the post-satellite era. With additional cross-validations, the reconstruction of TCG climatology is then extended to a pre-satellite period (1940-1960) during which TC base-track datasets are most uncertain. Our DL reconstruction reveals a significant missing of TCG in the current best-track data between September and November during the pre-satellite era. Such a TCG undercount in the best track data occurs mainly around 10-15$^\circ$N in the central WNP, while coastal regions show better consistency with DL reconstruction. These findings not only highlight the potential of DL for improving historical assessments of TC activity, but also advance our understanding of TCG processes by identifying key environmental conditions conducive to TC formation. The DL approach presented herein can be applied to other ocean basins, climate proxies, or reanalysis datasets for future TC climate studies. - oai:arXiv.org:2512.17711v1 - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Pushing the limits of one-dimensional NMR spectroscopy for automated structure elucidation using artificial intelligence + https://arxiv.org/abs/2512.18531 + arXiv:2512.18531v1 Announce Type: new +Abstract: One-dimensional NMR spectroscopy is one of the most widely used techniques for the characterization of organic compounds and natural products. For molecules with up to 36 non-hydrogen atoms, the number of possible structures has been estimated to range from $10^{20} - 10^{60}$. The task of determining the structure (formula and connectivity) of a molecule of this size using only its one-dimensional $^1$H and/or $^{13}$C NMR spectrum, i.e. de novo structure generation, thus appears completely intractable. Here we show how it is possible to achieve this task for systems with up to 40 non-hydrogen atoms across the full elemental coverage typically encountered in organic chemistry (C, N, O, H, P, S, Si, B, and the halogens) using a deep learning framework, thus covering a vast portion of the drug-like chemical space. Leveraging insights from natural language processing, we show that our transformer-based architecture predicts the correct molecule with 55.2% accuracy within the first 15 predictions using only the $^1$H and $^{13}$C NMR spectra, thus overcoming the combinatorial growth of the chemical space while also being extensible to experimental data via fine-tuning. + oai:arXiv.org:2512.18531v1 + physics.chem-ph + cs.LG + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Chanh Kieu, Thanh T. N. Nguyen, Duc-Trong Le, Duc Gia-Anh Hoang, Quang-Lap Luu, Binh T. Dang, Truong X. Ngo, Quang-Trung Luu, Tien D. Du, Khiem V. Mai + Frank Hu, Jonathan M. Tubb, Dimitris Argyropoulos, Sergey Golotvin, Mikhail Elyashberg, Grant M. Rotskoff, Matthew W. Kanan, Thomas E. Markland - Design, Testing and Numerical Modelling of a Low-Speed Wind Tunnel Gust Generator - https://arxiv.org/abs/2512.17732 - arXiv:2512.17732v1 Announce Type: new -Abstract: Understanding and accurately reproducing gust-induced unsteady aerodynamics is essential for improving load prediction, aeroelastic analysis, and control strategies in aircraft, uninhabited aerial vehicles, and wind turbines, particularly in regimes where nonlinear flow phenomena dominate. In this work, a low-speed wind tunnel gust generator based on oscillating vanes is designed, manufactured, and characterised through a combined experimental and numerical investigation. The system is intended to reproduce deterministic gust profiles relevant to aircraft, uninhabited aerial vehicles, and wind-turbine applications, operating in highly unsteady aerodynamic regimes. Experimental measurements using hot-wire anemometry are performed to quantify the generated gust field under a range of free-stream velocities, amplitudes, and forcing frequencies. In parallel, time-accurate CFD simulations are conducted using a deforming-mesh approach to validate the measurements and to analyse the flow physics associated with gust formation and propagation. Particular attention is given to the negative velocity peaks inherent to classical '1-cos' gust profiles. A modified vane motion protocol is proposed and shown to significantly reduce the negative peak factor while maintaining a substantial gust ratio. Numerical results reveal that secondary flow-angle variations arise from nonlinear interactions between vortices shed by adjacent vanes. - oai:arXiv.org:2512.17732v1 + Thermal characterization of suspended fine wires across continuum to free-molecular gas regimes using the 3$\omega$ method + https://arxiv.org/abs/2512.18591 + arXiv:2512.18591v1 Announce Type: new +Abstract: The 3$\omega$ method is widely used to measure the thermal conductivity and the specific heat of wires and thin films. These measurements are typically performed under high vacuum conditions, which justify the use of heat transfer models that exclude thermal losses to a surrounding fluid. Here, we study the effect of thermal conduction from a joule-heated wire to a surrounding gas on pressure-dependent 3$\omega$ measurements, and show how a one-dimensional (1D) heat-transfer model may be used to reliably determine the wire's thermal properties. We derive a full analytical solution of the 1D heat-transfer equation with finite heat-transfer coefficient $h$ and validate it experimentally using a 16-$\mu$m diameter platinum wire in air across pressures from $10^{-5}$ to $10^3$ mbar. We introduce a model for heat transfer between the wire and the surrounding gas based on kinetic gas theory that accurately describes the data across continuum to free-molecular gas regimes, with $h$ varying from near-zero in high vacuum to approximately 700 W/(m$^2\cdot$K) at atmospheric pressure. We show that use of a validated $h(p)$ model allows extracting both thermal conductivity $\kappa$ and volumetric heat capacity $\rho c_p$, whereas volumetric heat capacity can be extracted even without invoking a specific $h(p)$ model. Our approach facilitates the characterization of fine wires with moderate to low thermal conductivities and may enable accurate thermal measurements of suspended wires with diameters on the nanometer scale. + oai:arXiv.org:2512.18591v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1103/72dg-6d56 + Chuyue Peng, Joshua Ginzburg, Uri Dickman, Jacob Bair, Matthias Kuehne + + + Data-driven detached-eddy simulations based on explicit algebraic stress expressions for turbulent flows + https://arxiv.org/abs/2512.18609 + arXiv:2512.18609v1 Announce Type: new +Abstract: This work proposes a data-driven explicit algebraic stress-based detached-eddy simulation (DES) method. Despite the widespread use of data-driven methods in model development for both Reynolds-averaged Navier-Stokes (RANS) and large-eddy simulations (LES), their applications to DES remain limited. The challenge mainly lies in the absence of modelled stress data, the requirement for proper length scales in RANS and LES branches, and the maintenance of a reasonable switching behaviour. The data-driven DES method is constructed based on the algebraic stress equation. The control of RANS/LES switching is achieved through the eddy viscosity in the linear part of the modelled stress, under the $\ell^2-\omega$ DES framework. Three model coefficients associated with the pressure-strain terms and the LES length scale are represented by a neural network as functions of scalar invariants of velocity gradient. The neural network is trained using velocity data with the ensemble Kalman method, thereby circumventing the requirement for modelled stress data. Moreover, the baseline coefficient values are incorporated as additional reference data to ensure reasonable switching behaviour. The proposed approach is evaluated on two challenging turbulent flows, i.e., the secondary flow in a square duct and the separated flow over a bump. The trained model achieves significant improvements in predicting mean flow statistics compared to the baseline model. This is attributed to improved predictions of the modelled stress. The trained model also exhibits reasonable switching behaviour, enlarging the LES region to resolve more turbulent structures. Furthermore, the model shows satisfactory generalization capabilities for both cases in similar flow configurations. + oai:arXiv.org:2512.18609v1 physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Marinos Manolesos, Dimitris Gkiolas, Konstantinos Rekoumis, George Papadakis + Hao-Chen Liu, Zifei Yin, Xin-Lei Zhang, Guowei He - When and where higher-resolution climate data improve impact model performance - https://arxiv.org/abs/2512.17739 - arXiv:2512.17739v1 Announce Type: new -Abstract: Climate impact assessments increasingly rely on high-resolution climate and forcing datasets, under the premise that finer detail enhances both the accuracy and policy relevance of projections. Yet systematic evaluations of when and where higher resolution actually improves impact model outcomes remain limited, and it is unclear whether increasing spatial resolution consistently enhances performance across sectors, regions, and forcing variables. Here we show that gains in climate input accuracy and impact model performance are largest when moving from coarse (60 km) to intermediate (10 km) resolution, while further refinement to 3 km and 1 km yields more modest and inconsistent benefits. Using cross-sectoral simulations from the Inter-Sectoral Impact Model Intercomparison Project, we find that higher resolution substantially improves model skill in temperature-sensitive impact models and topographically complex regions, whereas precipitation-driven and low-relief systems show weaker and less systematic improvements. For temperature, both climate inputs and model outputs improve most strongly at the 60 km to 10 km transition, with diminishing gains at finer scales; for precipitation, some models even exhibit reduced performance beyond 10 km. These results highlight that optimal resolution depends on sectoral and regional context, and point to the need for improving model process representation and downscaling techniques so that added spatial detail translates into meaningful skill gains. For data providers, this implies prioritizing resolutions that maximize improvements where they matter most, while for modelling groups and users it underscores the need for explicit benchmarking of resolution choices in climate impact assessments. - oai:arXiv.org:2512.17739v1 - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Revisiting Mars' Induced Magnetic Field and Clock Angle Departures under Real-Time Upstream Solar Wind Conditions + https://arxiv.org/abs/2512.18629 + arXiv:2512.18629v1 Announce Type: new +Abstract: Mars lacks a global intrinsic dipole magnetic field, but its interaction with the solar wind generates a global induced magnetosphere. Until now, most studies have relied on single-spacecraft measurements, which could not simultaneously capture upstream solar wind conditions and the induced magnetic fields, thereby limiting our understanding of the system. Here, we statistically re-examine the properties of Mars' induced magnetic field by incorporating, for the first time, real-time upstream solar wind conditions from the coordinated MAVEN and Tianwen-1 observations. Our results are show that both solar wind dynamic pressure and the interplanetary magnetic field (IMF) magnitude enhance the strength of the induced magnetic field, but they exert opposite effects on the compression ratio: higher dynamic pressure strengthens compression, while stronger IMF weakens it. The induced field is stronger under quasi-perpendicular IMF conditions compared with quasi-parallel IMF, reflecting a stronger mass-loading effect. We further investigate the clock angle departures of the induced fields. They remain relatively small in the magnetosheath near the bow shock, increase gradually toward the induced magnetosphere, and become significantly larger within the induced magnetosphere. In addition, clock angle departures are strongly enhanced under quasi-parallel IMF conditions. Their dependence on upstream drivers further shows that, within the magnetosheath, clock angle departures are minimized under low dynamic pressure, high IMF magnitude, and low Alfven Mach number conditions. These results may enhance our understanding of solar wind interaction with Mars, and highlight the critical role of multi-point observations. + oai:arXiv.org:2512.18629v1 + physics.space-ph + astro-ph.EP + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Johanna T. Malle, Christopher P. O. Reyer, Yael Amitai, Andrey L. D. Augustynczik, Yaron Be'eri-Shlevin, Elad Ben-Zur, Peter Burek, Tarunsinh Chaudhari, Jinfeng Chang, Alessio Collalti, Daniela Dalmonech, Shouro Dasgupta, Iulii Didovets, Marc Djahangard, Laura Dobor, Louis Fran\c{c}ois, Simon N. Gosling, Fred F. Hattermann, Shaoshun Huang, Heike Lischke, Thomas Lorimer, Katarina Merganicova, Francesco Minunno, Mats Nieberg, Elizabeth J. Z. Robinson, Martin Schmid, Mikhail Smilovic, Ritika Srinet, Elia Vangi, Xue Yang, Rasoul Yousefpour, Ana I. Ayala, Daniel Mercado-Bettin, D\'annell Quesada-Chac\'on, Dirk N. Karger + Zhihao Cheng, Chi Zhang, Chuanfei Dong, Hongyang Zhou, Jiawei Gao, Abigail Tadlock, Xinmin Li, Liang Wang - Signatures of coherent energy transfer and exciton delocalization in time-resolved optical cross correlations - https://arxiv.org/abs/2512.17741 - arXiv:2512.17741v1 Announce Type: new -Abstract: We investigate how optical second-order cross correlations witness the quantum features of a prototype donor-acceptor light-harvesting unit. By considering a pair of detuned two-level emitters electronically coupled and incoherently driven to a non-equilibrium steady-state, we gain insight into how electronic quantum properties such as exciton eigenstate delocalization, coherent energy transfer and steady-state electronic coherence, are manifested in the joint probability of emission or optical second-order cross correlation. Specifically, we show that the frequency associated with oscillations present in time-resolved second-order cross correlation functions quantifies not only the time scale of coherent energy transfer but also the degree of delocalization of the exciton eigenstates. Furthermore, we show that time-resolved cross correlations directly witness steady-state electronic coherence. Our work strengthens the idea that measurements of the intensity quantum cross correlations can provide distinctive signatures of the quantum behavior of biophysical emitters. - oai:arXiv.org:2512.17741v1 - physics.chem-ph - physics.bio-ph - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Study of the impact of fast ions on core turbulence at rational surfaces via global gyrokinetic simulations + https://arxiv.org/abs/2512.18639 + arXiv:2512.18639v1 Announce Type: new +Abstract: In this work, the interplay between fast ions and safety factor rational surfaces is studied in a turbulent plasma via global nonlinear gyrokinetic simulations. Initially, the fast particles-induced enhancement of shearing structures from turbulence self-interaction is analyzed. Our study takes into account the competition between this mechanism and other fast ions effects, i.e. thermal profiles dilution and quasi-resonant interaction. We find the fast ions-induced reduction of destabilization threshold for the zonal modes to be a very efficient way to suppress turbulence. Indeed, it leads to the formation of regions where turbulent transport is reduced by 90\% of its original value. Furthermore, an $n=m=1$ fishbone is driven unstable inside the plasma and its interaction with turbulence is studied. We find the beat-driven zonal structure generate by this mode to further reduce turbulence when its presence does not drastically flatten the thermal profiles. + oai:arXiv.org:2512.18639v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Hallmann \'Oskar Gestsson, Alexandra Olaya-Castro + D. Brioschi, A. Di Siena, R. Bilato, A. Bottino, T. Hayward-Schneider, A. Mishchenko, E. Poli, A. Zocco, F. Jenko - Spectral finite-element formulation of the optimized effective potential method for atomic structure in the random phase approximation - https://arxiv.org/abs/2512.17757 - arXiv:2512.17757v1 Announce Type: new -Abstract: We present a spectral finite-element formulation of the optimized effective potential (OEP) method for atomic structure calculations in the random phase approximation (RPA). In particular, we develop a finite-element framework that employs a polynomial mesh with element nodes placed according to the Chebyshev-Gauss-Lobatto scheme, high-order $\mathcal{C}^0$-continuous Lagrange polynomial basis functions, and Gauss-Legendre quadrature for spatial integration. We employ distinct polynomial degrees for the orbitals, Hartree potential, and RPA-OEP exchange-correlation potential. Through representative examples, we verify the accuracy of the developed framework, assess the fidelity of one-parameter double-hybrid functionals constructed with RPA correlation, and develop a machine-learned model for the RPA-OEP exchange-correlation potential at the level of the generalized gradient approximation, based on the kernel method and linear regression. - oai:arXiv.org:2512.17757v1 - physics.comp-ph - physics.atom-ph - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Bridging the divide: Economic exchange and segregation in dual-income cities + https://arxiv.org/abs/2512.18680 + arXiv:2512.18680v1 Announce Type: new +Abstract: Segregation is a growing concern around the world. One of its main manifestations is the creation of ghettos, whose inhabitants have difficult access to well-paid jobs, which are often located far from their homes. In order to study this phenomenon, we propose an extension of Schelling's model of segregation to take into account the existence of economic exchanges. To approximate a geographical model of the city, we consider a small-world network with a defined real estate market. The evolution of the system has also been studied, finding that economic exchanges follow exponential laws and relocations are approximated by power laws. In addition to this, we consider the existence of delays in the actions of the agents, which mainly affect the happiness of those with fewer economic resources. Besides, the size of the economic exchange plays a crucial role in overall segregation. Despite its simplicity, we find that our model reproduces real-world situations such as the separation between favoured and handicapped economic areas, the importance of economic contacts between them to improve the distribution of wealth, and the existence of efficient and cheap transport to break the poverty cycles typical of disadvantaged zones. + oai:arXiv.org:2512.18680v1 + physics.soc-ph + cond-mat.stat-mech + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shubhang Krishnakant Trivedi, Phanish Suryanarayana + 10.1016/j.physa.2025.131211 + Physica A, Volume 683, 131211 (2026) + D. Ortega, E. Korutcheva - Irreversible thermalization vs reversible dynamics mediated by anomalous correlators: Wave turbulence theory and experiments in optical fibers - https://arxiv.org/abs/2512.17777 - arXiv:2512.17777v1 Announce Type: new -Abstract: We theoretically and experimentally investigate spontaneous self-organization in a conservative (Hamiltonian) turbulent wave system, operating far from thermodynamic equilibrium. Our system is governed by two coherently coupled nonlinear Schr\"odinger equations, describing the polarization evolution of light in a dispersive nonlinear optical fiber. The analysis reveals the emergence of two fundamentally distinct turbulent regimes. In a first regime, the waves undergo a slow, irreversible thermalization process, which is accurately described by the wave turbulence kinetic equation and the associated H-theorem of entropy growth. In stark contrast with this expected irreversible process, we identify a second different regime, where strong phase-correlations spontaneously emerge, giving rise to a fast reversible oscillatory dynamics of the normal correlator and anomalous phase-correlator. Experimental observations confirm the occurrence of both irreversible thermalization and reversible dynamics mediated by the anomalous correlated fluctuations. - oai:arXiv.org:2512.17777v1 + Sub-nanometer 3D morphometric precision of polarisation-resolved wide-field optical extinction microscopy determines the roundness of individual gold nanospheres + https://arxiv.org/abs/2512.18696 + arXiv:2512.18696v1 Announce Type: new +Abstract: Quantitative polarisation-resolved optical extinction microscopy of individual plasmonic nanoparticles has recently been introduced as a powerful tool to characterise the nanoparticle's morphology with a precision comparable to electron microscopy, while using a simple optical microscope [Nanoscale 12, 16215 (2020)]. Here we extend the technique by adding measurements for radial polarisation in the condenser back focal plane, probing plasmonic resonances polarised in axial direction. The combined linear and radial polarisation measurements provide a significantly enhanced precision of the retrieved 3D morphology, as we show on defect-free ultra-uniform gold nanospheres of 30 nm nominal diameter characterised by transmission electron microscopy. The measured cross-sections are quantitatively described by an ellipsoid model, determining the three semi-axes and rotation angles by fitting the measurements. Evaluation the distribution of the fit error across the set of measured particles, the material permittivity dataset and surface damping parameter g providing the best fit are found to be the single crystal dataset by Olmon et al. [Phys. Rev. B 86, 235147 (2012)] and g = 1.8, respectively. The precision of the retrieved aspect ratio is below 5%, and all three ellipsoidal semi-axes are determined with an impressive precision of 0.25 nm. Notably, corrections to the Rayleigh-Gans ellipsoid model due to retardation are significant even though the particle diameters are more than an order of magnitude smaller than the wavelength, and taking them into account improves the accuracy to below a nanometer. + oai:arXiv.org:2512.18696v1 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + cond-mat.mes-hall + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - T. Torres, J. Garnier, L. Zanaglia, M. Ferraro, C. Michel, V. Doya, J. Fatome, B. Kibler, S. Wabnitz, A. Picozzi, G. Millot + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Lukas M Payne, Furqan Alabdullah, Paola Borri, Wolfgang Langbein - Two-photon light-sheet live imaging at kilohertz frame rate using birefringence-based pulse splitting - https://arxiv.org/abs/2512.17783 - arXiv:2512.17783v1 Announce Type: new -Abstract: Multiphoton microscopy is widely used for live imaging. However, its acquisition speed remains limited by fluorophore emission rates and photodamage. To increase the pixel rate of a two-photon microscope beyond a few megahertz (MHz), multi-point parallelized schemes have been proposed. Two-photon (2P) light-sheet microscopy emerges as an effective approach for high-speed multiphoton imaging of live specimens, as it enables parallelized excitation while minimizing the required laser power. However, optimizing the signal-to-photodamage ratio in 2P light-sheet microscopy requires to precisely control the illumination parameters, including both wavelength and pulse frequency. Since conventional femtosecond laser sources generally do not allow independent modulation of these parameters, the development of low-cost, efficient and robust strategies to modulate the temporal excitation profile is essential to fully exploit the advantages of 2P light-sheet microscopy. Here, we introduce a compact pulse splitting scheme that meets these criteria. We used cascaded birefringent crystals to convert each excitation laser pulse into an adjustable sequence of collinear sub-pulses. We demonstrate its effectiveness in optimizing 2P light-sheet imaging of live zebrafish embryos. We analyze the impact of pulse splitting on photobleaching, nonlinear photodamage, and imaging performance. Additionally, we demonstrate high-speed 2P imaging of the beating heart and brain calcium dynamics using red fluorophores in live embryos. We achieve kilohertz imaging frame rate, reaching more than 150 MHz pixel rates with fluorescent signal levels above 10 $photons.pixel^{-1}$ using a laser mean power and a peak intensity in the range of 100 mW and 0.1 $TW.cm^{-2}$ at the sample, respectively. This adjustable pulse-splitting scheme allows full advantage to be taken of light-sheet illumination for fast in vivo 2P imaging. - oai:arXiv.org:2512.17783v1 - physics.optics - physics.app-ph + Load-Aware Calibration of EMG-Driven Musculoskeletal Models for Accurate and Generalizable Joint Torque Estimation + https://arxiv.org/abs/2512.18710 + arXiv:2512.18710v1 Announce Type: new +Abstract: Accurate EMG-driven musculoskeletal (MSK) modeling is critical for biomechanics, rehabilitation, and assistive technology. However, most models calibrate parameters under a single load, ignoring the fact that tasks with similar kinematics may differ in mechanical demand. This study introduces a load-aware calibration framework to improve joint torque prediction accuracy and generalizability. Surface EMG and joint kinematics were recorded from eleven participants during elbow flexion-extension under 0, 2, and 4\,kg loads. We evaluated three calibration strategies (load-specific, global, cross-load) and three optimization frameworks (simulated annealing (SA), particle swarm optimization (PSO), and hybrid PSO-pattern search (PSO-PS)). Results indicate that load-specific calibration significantly improves performance, with lower RMSE and higher correlation ($r > 0.75$). Parameters related to muscle force, fiber length, and activation dynamics showed high load sensitivity. PSO-based methods yielded more consistent and physiologically plausible estimates than simulated annealing. The proposed framework enables MSK models to distinguish between visually similar but mechanically distinct tasks, supporting robust subject-specific modeling for clinical and real-world applications. + oai:arXiv.org:2512.18710v1 physics.bio-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Lei Zhu, Dale Gottlieb, Vincent Maioli, Antoine Hubert, Fr\'ed\'eric Druon, Pierre Mahou, Emmanuel Beaurepaire, Willy Supatto + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Rajnish Kumar, Suriya Prakash Muthukrishnan, Lalan Kumar, Sitikantha Roy - The influence of energy-containing scales on the distribution of spectral energy transfers - https://arxiv.org/abs/2512.17804 - arXiv:2512.17804v1 Announce Type: new -Abstract: We present computations of individual mode-to-mode energy transfers from direct numerical simulations of homogeneous isotropic turbulence. Unlike previous approaches based on shell-filtered velocity fields, this method distinguishes between the energy exchanged by each pair of modes within a triad. We introduce a potential function based on the energy content of the modes involved and show that it predicts the distribution of intense energy transfers in the vicinity of the sampling mode considered. By performing simulations with forcing applied at intermediate wavenumbers, we demonstrate that the region of most intense transfers is determined by the spectral location of the energy-containing scales rather than by the local or nonlocal character of the triad. Direct energy exchanges with the energy-containing range are suppressed by geometric constraints from the divergence-free condition, but persist as residuals when the sampling mode is close to the energy-containing scales. The comparison with an estimator derived from EDQNM theory shows good agreement and recovers the forward, scale-local nature of energy transfer consistent with the cascade picture. - oai:arXiv.org:2512.17804v1 - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Line lasing in a two-dimensional lattice of orbital photonic resonators + https://arxiv.org/abs/2512.18719 + arXiv:2512.18719v1 Announce Type: new +Abstract: The engineering of specialty lasers with unconventional mode structures is one of the modern challenges in the development of integrated coherent sources. Examples include the use of bound states in the continuum, microlasers with orbital angular momentum, Dirac-band lasers and topological lasers. In this work we engineer a two-dimensional lattice of coupled micropillars with lasing line modes. We use a convenient combination of orbital photonic modes to design photonic bands which are flat in one direction and dispersive in the perpendicular one giving rise to line lasing modes. Such an architecture opens the possibility of implementing densely packed lasing matrices in compact two dimensional lattices. + oai:arXiv.org:2512.18719v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Arthur Couteau, Panayotis Dimopoulos Eggenschwiler, Patrick Jenny + Tony Mathew Blessan, Bastian Real, Marijana Milicevic, Isabelle Sagnes, Aristide Lema\'itre, Luc Le Gratiet, Abdelmounaim Harouri, Sylvain Ravets, Jacqueline Bloch, Cl\'ement Hainaut, Alberto Amo - Biswas-Chatterjee-Sen (BChS) kinetic exchange opinion model on modular networks - https://arxiv.org/abs/2512.17810 - arXiv:2512.17810v1 Announce Type: new -Abstract: We study opinion formation in a society where agents interact on a modular network generated using a stochastic block model (SBM). Opinion dynamics is modeled through the Biswas-Chatterjee-Sen (BChS) kinetic exchange model, in which agents undergo pairwise interactions that could be positive or negative. By tuning the relative strength of intra- and inter-group connectivity inherent to the SBM, as well as the disagreement probability, we identify distinct collective phases. In particular, we observe a robust regime with strong intragroup ordering but no global consensus, in addition to fully ordered and disordered states. These results demonstrate how modular interaction structure can qualitatively alter collective opinion dynamics and hinder consensus formation. - oai:arXiv.org:2512.17810v1 - physics.soc-ph - cond-mat.stat-mech - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Linear and nonlinear stability of rate-and-state faults + https://arxiv.org/abs/2512.18729 + arXiv:2512.18729v1 Announce Type: new +Abstract: Models of faults incorporating slip rate- and state-dependent friction have reproduced phenomena from spontaneous slow, aseismic slip to earthquake-generating dynamic rupture. Exhaustive explorations of model parameter space regularly show sudden transitions in behavior. However these boundaries are poorly constrained analytically, with commonly used scalings derived assuming conditions that do not resemble those of the models. In this work, we demonstrate that an analysis of linear stability can reflect model conditions. We examine two scenarios that move beyond the classical case of the uniform sliding of an unbounded fault: an asperity driven by the steady creep of its surroundings, and a finite fault experiencing a constant rate of shear loading. We identify the critical fault dimension $L_c$ at which point linear stability is lost. Beyond this linear regime, the non-linear nature of friction law implies the loss of memory of loading conditions as instability progresses and the existence of universal solutions describing this process. We refine prior analyses of this non-linear instability and find the minimum fault size that can support self-sustaining, unstable acceleration towards dynamic rupture. We examine the role of the state evolution law and delineate conditions under which faults may be linearly stable but non-linearly unstable, requiring finitely large perturbations to trigger instability. On the basis of numerical solutions, approximate but accurate algebraic expressions for the transition boundaries are presented. These results provide a means for careful model design and to easily delimit plausible regions of parameter space when considering physical observations. + oai:arXiv.org:2512.18729v1 + physics.geo-ph + Tue, 23 Dec 2025 00:00:00 -0500 new - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hrishidev Unni, Soumyajyoti Biswas, Anirban Chakraborti + http://creativecommons.org/licenses/by-sa/4.0/ + Robert C. Viesca, Dmitry I. Garagash - Fluid-inertia torques from particle-shape symmetry - https://arxiv.org/abs/2512.17822 - arXiv:2512.17822v1 Announce Type: new -Abstract: Numerical simulation of particle motion in fluids at low particle Reynolds numbers is often based on empirical force and torque models obtained by fitting force and torque from ab-initio computations for simple particle shapes such as spheres, spheroids, or cylindrical disks and fibres. To do the same for more complex particles shapes, one needs to first know how particle shape constrains the dependence of force and torque on flow velocity, its gradient, and on particle orientation. Here we use symmetry analysis and perturbation theory to determine the form of the hydrodynamic torque on a particle settling in a quiescent fluid at low but non-zero particle Reynolds numbers, for particle shapes with different point-group symmetries. The symmetry conclusions are verified by comparing with explicit calculations for nearly spherical particles. - oai:arXiv.org:2512.17822v1 - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Source quantification by mobile gamma-ray spectrometry systems: A Bayesian approach + https://arxiv.org/abs/2512.18769 + arXiv:2512.18769v1 Announce Type: new +Abstract: Accurately quantifying gamma-ray sources from mobile gamma-ray spectrometry surveys has remained a fundamentally elusive, long-standing inverse problem at the interface of nuclear and computational physics. Here, we present a full-spectrum Bayesian inference framework that resolves this inverse problem by combining high-fidelity, platform-dynamic Monte Carlo template generation with Bayesian inversion. Applying this methodology to airborne measurements benchmarked against laboratory and in-situ ground truths, we demonstrate accurate and robust quantification of both natural and anthropogenic radionuclides under field conditions. By improving activity estimates by an order of magnitude, providing principled uncertainty quantification, and rigorously accounting for overdispersion, this framework opens the way to a more statistically rigorous and physics-informed era of mobile gamma-ray spectrometry, unlocking enhanced inference capabilities in emergency response, environmental monitoring, nuclear security, and planetary exploration. + oai:arXiv.org:2512.18769v1 + physics.ins-det + physics.app-ph + physics.comp-ph + physics.data-an + physics.geo-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - L. Sundberg, F. Candelier, N. Fintzi, G. Voth, J. L. Pierson, K. Gustavsson, B. Mehlig + David Breitenmoser, Alberto Stabilini, Malgorzata Magdalena Kasprzak, Sabine Mayer - First results of a Monolithic Active Pixel Sensor with Internal Signal Gain Fully Integrated in a 180 nm CMOS Technology - https://arxiv.org/abs/2512.17824 - arXiv:2512.17824v1 Announce Type: new -Abstract: Dense tracking environments in experiments at CERN's High-Luminosity LHC and future FCC experiments call for an increased use of timing information in addition to the position measurement of pixel detectors. This adds one dimension to the information available, and is essential for pile-up mitigation at high luminosity. The CASSIA sensor project (CMOS Active SenSor with Internal Amplification) focuses on the development of pixel matrices with internal charge multiplication based on monolithic CMOS sensor technologies suitable for application as charged particle tracking and timing detectors. CMOS sensors with in-pixel internal amplification would result in higher signal amplitudes having an improved signal-to-noise ratio, better time resolution and increased sensitivity, making them attractive for high-radiation environments. Their monolithic integration in small pixels reduces the input capacitance of a front-end amplifier and power dissipation making it suitable for fine-pitch low-power detectors. Fast signal rise time due to internal charge amplification improves the response time and timing resolution, all of which makes such a technology attractive for future 4D tracking applications in HEP experiments. This paper presents the first results of the CASSIA sensor, a novel MAPS which uses gain layers fully integrated in a 180nm imaging process to achieve internal signal amplification. In the first measurements presented here we demonstrate the gain behaviour of different pixel implant designs and show that the sensor can be operated with low gain proportional mode as LGAD sensor at lower voltages and as SPAD sensor at higher voltages. - oai:arXiv.org:2512.17824v1 - physics.ins-det - hep-ex - Mon, 22 Dec 2025 00:00:00 -0500 + Discrete inflow and drainage dynamics of a thin film over a stalagmite of variable shape + https://arxiv.org/abs/2512.18771 + arXiv:2512.18771v1 Announce Type: new +Abstract: Stalagmites in karstic caves preserve valuable palaeoclimate records through calcium-rich layered deposits, presenting curvature variations both across and within individual stalagmites. Stalagmites always remain covered by a thin water film fed by a discrete inflow of drops, which bring in new ions in solution for the stalagmites to grow. However, the gravity-induced drainage of this film and its response to the stalagmite underneath shape and the discrete drop inflow remain poorly characterised in existing growth models. To address these limitations, we develop a theoretical framework that captures the combined effects of shape curvature and discrete drop inflow on thin film drainage dynamics, starting from Reynolds lubrication theory expressed in curvilinear coordinates. From there, we show that the limiting cases of thickness-dominated and inclination-dominated drainage translate into distinct scaling laws for both the front propagation position and stationary film thickness. We further validate these results by numerically solving the governing equations. Finally, experimental measurements conducted in both cave and lab settings confirm the predicted stationary film thickness. Our findings provide insights into the influence of substrate shape and inflow dynamics on thin film drainage, with implications for stalagmite growth modelling and other gravity-driven surface flows. + oai:arXiv.org:2512.18771v1 + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Heinz Pernegger (CERN, Experimental Physics Department, Geneva, Switzerland), Emma Kate Anderson (CERN, Experimental Physics Department, Geneva, Switzerland), Paula Bartulovi\'c (University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia), Ivan Berdalovi\'c (University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia), Marc Giroux de Foiard Brown (CERN, Experimental Physics Department, Geneva, Switzerland), Sebastian Haberl (CERN, Experimental Physics Department, Geneva, Switzerland, University of Innsbruck, Innsbruck, Austria), Matija Jugovi\'c (University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia), Anastasia Kotsokechagia (CERN, Experimental Physics Department, Geneva, Switzerland), Jenny Lunde (CERN, Experimental Physics Department, Geneva, Switzerland, University of Oslo, Oslo, Norway), Borna Po\v{z}ar (CERN, Experimental Physics Department, Geneva, Switzerland), Tomislav Suligoj (University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb, Croatia) + Justine Parmentier, Vincent E. Terrapon, Tristan Gilet - Theory of Non-Dichroic Enantio-Sensitive Chiroptical Spectroscopy - https://arxiv.org/abs/2512.17840 - arXiv:2512.17840v1 Announce Type: new -Abstract: We show that the photoelectron angular distributions produced by elliptical and cross-polarized two-color laser fields interacting with randomly oriented chiral molecules decompose into four irreducible representations of the $D_{2h}$ point group. One of these ($A_u$) corresponds to a non-dichroic enantiosensitive (NoDES) contribution. This NoDES contribution has opposite sign for opposite enantiomers but remains invariant under reversal of the field ellipticity, enabling chirality detection that is robust against variations of the relative phase between orthogonal field components. We propose a protocol to isolate this component using only two velocity-map imaging projections and validate it through numerical simulations. Our calculations, performed in the two-photon resonantly-enhanced ionization, multi-photon, and strong-field ionization regimes with cross-polarized two-color fields show that the NoDES signal reaches about 1\% of the energy-resolved ionization yield, comparable to photoelectron circular dichroism and much larger than standard magnetic-dipole chiroptical effects. NoDES spectroscopy thus provides a symmetry-protected and phase-robust route to probe molecular chirality on the ultrafast time scale. The experimental confirmation of our theory is presented in the companion paper [L. Fede et al., arXiv (2025)]. - oai:arXiv.org:2512.17840v1 - physics.chem-ph + Quantitative ultrasound imaging of bone: anatomical images, tissue structural quality, and pulsatile blood flow + https://arxiv.org/abs/2512.18793 + arXiv:2512.18793v1 Announce Type: new +Abstract: We propose an ultrasound approach which provides, with one single examination and one single device, access to three bone biomarkers: anatomy, tissue quality and blood flow. It unlocks ultrasound imaging inside bone by accounting for ultrasound wave speed heterogeneity and anisotropic wave refraction. This study reports the first \emph{in vivo} evaluation with a comparison to peripheral Quantitative Computed Tomography (pQCT) and modulations of blood flow. Anatomical multi-layer bone-corrected reconstruction was validated at the tibia of healthy volunteers against pQCT and showed agreement on bone cortex interfaces. Estimation of axial and radial ultrasound wave speeds in cortical bone tissue (i.e. along the tissue symmetry axis and normal to it) demonstrated good reproducibility and positive correlation with bone mineral density measured by pQCT. Pulsatile blood flow was mapped and quantified in cortical and medullary regions. A directional ray selection method was developed to enhance blood signal extraction by reducing strong specular reflections originating from the outer and inner surfaces of the bone cortex. Physiological and non-physiological modulations of blood flow, namely head-up/head-down tilt table maneuvers and arterial occlusions, demonstrated the method sensitivity to blood flow variations. For the first time, reactive hyperemia was observed inside bone cortex. These results demonstrate the feasibility of a portable, non-ionizing, and quantitative ultrasound approach for structural, anatomical, and vascular characterization of bone tissue. This approach may offer new diagnostic capabilities for bone disorders, for instance osteoporosis, delayed fracture healing or osteonecrosis. + oai:arXiv.org:2512.18793v1 + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Gabrielle Laloy-Borgna, Nastassia Navasiolava, Pim Hutting, Andr\'ea Bertona, Amadou S. Dia, S\'ebastien Salles, Anthony Aug\'e, Alice Mazzolini, Quentin Grimal, Olivier Lucidarme, Herv\'e Locrelle, Jacques-Olivier Fortrat, Laurence Vico, Marc-Antoine Custaud, Guillaume Renaud + + + A Segmented Heater-Driven, Low-Loss, Reconfigurable Photonic Phase-Change Material-Based Phase Shifter + https://arxiv.org/abs/2512.18800 + arXiv:2512.18800v1 Announce Type: new +Abstract: Phase-change material (PCM)-based non-volatile multilevel phase shifters are key components in photonic integrated circuits. Electrically, multiple phase levels can be encoded by controlling the heater power and employing different microheater architectures to induce varying degrees of PCM amorphization. However, encoding a large number of levels is not straightforward. In this work, we first investigate a phase shifter structure based on a GeSe PCM integrated on top of a silicon-on-insulator waveguide, employing a simple rectangular-shaped heater under pulse-width modulation (PWM). We numerically demonstrate that multilevel phase shifts can be achieved because of non-uniform heating in the GeSe PCM layer. However, the resulting phase levels for this basic configuration are highly non-linear because of the uniform power dissipation along the light propagation direction characterized by the same cross-section. To overcome this limitation, we designed a novel PCM-based phase shifter with a segmented heater whose width gradually increases along the light propagation direction. This configuration enables the encoding of hundreds of well-spaced phase levels between 0 and $\pi$, facilitated by smoother amorphization arising from the combined effects of non-uniform heating across segments and within each segment, while achieving an insertion loss of only 0.6 dB in the worst case. Furthermore, when evaluating both heater architectures under pulse amplitude modulation (PAM) at a fixed pulse duration, we observe behavior consistent with the trends observed for PWM, confirming the superior performance of the segmented heater design. + oai:arXiv.org:2512.18800v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Ranjeet Dwivedi, Agraj Yadav, Regis Orobtchouk, Benoit Charbonnier, Stephane Malhouitre, Pierre No\'e, Fabio Pavanello + + + Point Charges in Classical Electrodynamics + https://arxiv.org/abs/2512.18802 + arXiv:2512.18802v1 Announce Type: new +Abstract: LaTeX transcription (2025) of a 1989 honours thesis (University of Adelaide) on point charges in classical electrodynamics and the Lorentz-Dirac radiation-reaction equation. The thesis reviews the retarded field of an arbitrarily moving charge, energy-momentum conservation, and derives the Lorentz-Dirac equation via momentum balance. It discusses self-interaction and mass renormalization, and presents world-line self-field definitions including retarded averaging and an analytic continuation approach. Appendices include Mathematica listings used to obtain near-world-line expansions of the field and related quantities. + oai:arXiv.org:2512.18802v1 + physics.class-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jonathan Baxter + + + Energetically-dominant Sunward-Propagating Alfv\'en Waves Near 1 au and Their Relation to Large-scale Magnetic Switchbacks + https://arxiv.org/abs/2512.18806 + arXiv:2512.18806v1 Announce Type: new +Abstract: In this letter, we investigate the population of energetically-dominant sunward-propagating Alfv\'en waves (SAWs) using more than 20 years of data provided by the Wind spacecraft near 1 au. We refer to SAWs as energetically-dominant sunward-propagating Alfv\'en waves within inertial range scales. Key parameters such as normalized cross helicity, plasma incompressibility, and magnetic incompressibility are used to determine the SAWs. Incorporating the polarity of the heliospheric magnetic field, AW modes are identified, which enables the determination of the propagation direction. Occurrence rates of SAWs vary from 1% to 14% depending on the time scale and solar wind stream type considered. Particularly, the relationship between large-scale magnetic field switchbacks (SBs) and SAWs (for a 1-hour long time scale) is investigated. A methodology utilizing pitch angle distributions of suprathermal electron strahl is employed to identify inverted magnetic field topology. The intervals containing SAWs are cross-referenced and examined with intervals identified as SBs. For a sample of 1636 1-hour SAW intervals, 17.5% are associated with magnetic field switchbacks occurring at scales larger than one hour. The analysis lends support to the idea of switchbacks as one of the candidate sources for a portion of the SAW population. + oai:arXiv.org:2512.18806v1 + physics.space-ph + astro-ph.EP + astro-ph.SR + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Nickolas Giardetti, Sofiane Bourouaine, Jean C. Perez + + + Endoplasmic Reticulum Structure Determines Optimal Ribosome Density + https://arxiv.org/abs/2512.18811 + arXiv:2512.18811v1 Announce Type: new +Abstract: Recent work has shown an increasing interest in understanding the structure of the endoplasmic reticulum (ER) and how ribosomes are displayed on it. Here we present a model that explains a physical reason for why the cell creates different structures of the ER. Due to the diffusion of biomolecules, we find that flat sheets and a matrix of tubules have different regimes of optimized capture efficiency. We extend the model to explain the observed difference in density of ribosomes on the structures of the ER. Due to the capture efficiency of tubules, less ribosomes are needed on those structures. For flat sheets, more ribosome coverage at biological separation distance is needed to match the same fraction of relative flux. We then push the model to predict that depending on the future life of the translated protein and overall demand for protein expression, the cell will utilize one structure of the ER over another. Predictions are compared with experimental data. + oai:arXiv.org:2512.18811v1 + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Benjamin Tang + + + Simulation Driven Design of a Multilayer Plasmonic Sensor Using Cu Ni and BaTiO3 for Waterborne Pathogen Detection + https://arxiv.org/abs/2512.18816 + arXiv:2512.18816v1 Announce Type: new +Abstract: We present a simulation guided design for a multilayer surface plasmon resonance (SPR) based biosensor capable of detecting refractive index changes in a target induced by analytes. Surface plasmons are excited using a hybrid Kretschmann configuration with a calcium fluoride (CaF2) prism under transverse magnetic polarization illumination. In the sensing architecture, copper (Cu) serves as the plasmonic metal and is overlaid with a thin nickel (Ni) layer to prevent oxidation. To enhance analyte coupling and electromagnetic field confinement, a dielectric layer of barium titanium oxide (BaTiO3) along with a monolayer of graphene oxide (GO) is incorporated. The multilayer structure is iteratively optimized using the transfer matrix method for angular interrogation at a wavelength of 1064 nm, focusing on key performance parameters such as sensitivity, minimum reflectivity, and figure of merit (FOM). Finite element method based simulations confirm efficient surface plasmon excitation, with optimal layer thicknesses of 30 nm for Cu and 5 nm for BaTiO3. The proposed SPR based sensor (CaF2 Cu Ni BaTiO3 GO) achieves a sensitivity of 157.8 deg per RIU and a figure of merit of 17.48 RIU minus one while detecting the presence of Escherichia coli bacteria in water, demonstrating its potential for waterborne pathogen sensing applications. + oai:arXiv.org:2512.18816v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + 10.1109/NMDC64551.2025.11233969 + 2025 IEEE 20th Nanotechnology Materials and Devices Conference (NMDC) October 9-11 2025 + R. Runthala, V. K. Venkatesh, D. Gupta, P. Arora + + + A physics-informed, plug-and-play dose engine for gradient-based radiotherapy treatment planning + https://arxiv.org/abs/2512.18863 + arXiv:2512.18863v1 Announce Type: new +Abstract: Radiotherapy treatment planning remains a time-intensive iterative process requiring expert intervention in commercial treatment planning system (TPS). While machine learning approaches have demonstrated promise, most remain depedent on TPS-based dose calculation or surrogate dose models, preventing direct optimization of deliverable treatment plan parameters. + We propose PyDoseRT (PDRT), a physics-informed, GPU-accelerated dose engine implemented in PyTorch that computes dose distributions directly from treatment delivery parameters (i.e., MLC leaf positions, jaw positions, gantry angles, and monitor units). The engine preserves gradient information throughout the dose computation pipeline, enabling gradient-based optimization of hardware-constrained treatment plans without the reliance on a commercial TPS. + PDRT was evaluated on 19 and 162 clinical VMAT prostate cancer plans from two hospitals (with different treatment machines). When recalculating clinical plans, PDRT achieved high 3D gamma pass rates (mean 96.8% for 2%/2 mm and 98.9% for 3%/3 mm, depending on cohort). All optimized plans converged to clinically acceptable solutions and passed deliverability verification when imported into a commercial TPS. + This physics-informed framework eliminates TPS dependency for radiotherapy optimization research by enabling gradient-based planning while ensuring that delivery parameters remain in the machine-feasible range. The gradient-enabled dose engine allows exploration of novel optimization strategies and objective functions while maintaining clinical validity. The proposed approach provides a research platform for investigating real-time adaptive radiotherapy concepts, automated planning workflows, and TPS-independent optimization strategies, and democratizing radiotherapy research, by exposing gradient-enabled, hardware-aware, open-source dose computation. + oai:arXiv.org:2512.18863v1 + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Attila Simk\'o, Matthias Kronsteiner, Simon Glatzer, Minh Vu, Josef A. Lundman, Joakim Jonsson, J\"orgen Olofsson, Kristina Sandgren, Wolfgang Lechner, Dietmar Georg, Tommy L\"ofstedt, Tufve Nyholm, Anders Garpebring, Gerd Heilemann + + + Making Quantum Accessible: A Seven-Category Framework for K-12 Quantum Education + https://arxiv.org/abs/2512.18886 + arXiv:2512.18886v1 Announce Type: new +Abstract: We conducted a literature review and expert interviews to determine the most common methods being used to teach quantum physics and quantum computing concepts to primary and secondary students. Based on the findings of this review, we provide a framework of seven categories of teaching approaches for teaching mathematically accessible quantum concepts; they are Defamiliarization, Quantum Picturalism, Spin-First Approach, Einstein-First Approach, Many Paths Approach, Historical Development Approach and Game-based Quantum Learning. We summarise each of these teaching methods and overview their advantages and disadvantages of each method. Our framework makes it easy for physics educators to embrace the diverse methods of teaching quantum physics and quantum computing at the primary and secondary level. + oai:arXiv.org:2512.18886v1 + physics.ed-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Rhea Fernandez, Sarah Hagstrom, Liesel Malanos, Lachlan McGinness, Madeline Mitchell, Saskia Schultz, Elizabeth Sexton + + + A Fixed-Volume Variant of Gibbs-Ensemble Monte Carlo Yields Significant Speedup in Binodal Calculation + https://arxiv.org/abs/2512.18899 + arXiv:2512.18899v1 Announce Type: new +Abstract: Gibbs-ensemble Monte Carlo (GEMC) is a powerful method for calculating the gas-liquid binodals of simple models and small molecules, but is too demanding computationally for realistic models of proteins. Here we discover that the main reason for long simulations is that volume exchange is very slow to achieve, and develop a variant GEMC without volume exchange. The key is to determine an appropriate initial density. Test of this fixed-volume GEMC method on Lennard-Jones and patchy particles shows enormous speedup without any loss of accuracy in predicted binodals. The fast speed of fixed-volume GEMC promises many applications. + oai:arXiv.org:2512.18899v1 + physics.chem-ph + physics.bio-ph + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Sanbo Qin, Huan-Xiang Zhou + + + Visualizing and Optimizing Phase Matching in Nonlinear Guided-mode Resonators with the Green's Function Integral Method + https://arxiv.org/abs/2512.18929 + arXiv:2512.18929v1 Announce Type: new +Abstract: Efficient nonlinear frequency conversion in nanophotonics requires not only strong fundamental field but also precise phase matching among distributed nonlinear sources. Here, we develop the two-dimensional Green's function integral method (GFIM), which enables direct visualization and optimization of phase matching in nonlinear guided-mode resonators. Using GFIM phase analysis, we generalize the phase-matching factor (PMF) as a rigorous metric of spatial phase coherence in harmonic generation, revealing severe phase mismatch in conventional guide mode resonators. Guided by phase-matching profiles, we propose design strategies to improve the phase coherence, particularly by introducing a high-index waveguide layer that confines the fundamental field in the nonlinear material to regions where the harmonic Green's function varies slowly. This configuration achieves a PMF exceeding 0.91, approaching the ideal value of unity, and yields a record SHG efficiency of 26.7% at a low pump intensity of 2 kW/$\mathrm{cm}^2$. These results establish the GFIM-based phase-matching visualization as an effective strategy for compact, high-performance nonlinear photonic devices. + oai:arXiv.org:2512.18929v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Chengkang Liang, Quanying Li, Jiale Xu, Pingqi Gao, Jiancan Yu + + + Non-Inductive Current Start-Up Using Multi-Harmonic Electron Cyclotron Wave and Current Ramp-Up Through Combined Electron Cyclotron Wave and Ohmic Heating in EXL-50U Spherical Torus + https://arxiv.org/abs/2512.18941 + arXiv:2512.18941v1 Announce Type: new +Abstract: The non-inductive current start-up by multi-harmonic electron cyclotron wave has been systematically investigated in the EXL-50U spherical torus. Significant enhancements of the driven current with increasing number of resonance layers have been demonstrated by variation of the number of harmonic resonance layers of the ECW through adjustment of the magnetic field or plasma cross section. The critical role of multi-harmonic ECW in enhancing the driven current has been experimentally verified for the first time. To explain the related experimental observations, a physical mechanism involving multi-harmonic heating, multiple reflections, and multi-pass absorption - leading to the generation of high-energy electrons via X-mode wave or electron Bernstein wave has been proposed. The current drive capacity of the first harmonic extraordinary mode of the ECW has also been experimentally confirmed for the first time. After the application of Ohmic heating during the current ramp-up phase, the current drive efficiency of ECW is further enhanced. Leveraging the synergistic effect between ECW and Ohmic heating, EXL-50U achieved a plasma current of 1 MA, with the non-inductively driven current fraction reaching 70%. + oai:arXiv.org:2512.18941v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xinchen Jiang, Yuejiang Shi, Yueng-Kay Martin Peng, Shaodong Song, Wenjun Liu, Xianming Song, Xiang Gu, Ji Qi, Dong Guo, Debabrata Banerjee, Lili Dong, Zhenxing Wang, Chunyan Li, Junquan Lin, Pingwei Zheng, Haojie MA, Huasheng Xie, Jiaqi Dong, Qingwei Yang, Yunfeng Liang, Baoshan Yuan, Xianmei Zhang, Minsheng Liu, EXL-50U team + + + Evolutionary Cooperation with Game Transitions via Markov Decision Chain in Networked Population + https://arxiv.org/abs/2512.18972 + arXiv:2512.18972v1 Announce Type: new +Abstract: Individual cooperative strategy influences the surrounding dynamic population, which in turn affects cooperative strategy. To better model this phenomenon, we develop a Markov decision chain based game transitions model and examine the dynamic transitions in game states of individuals within a network and their impact on the strategy's evolution. Additionally, we extend single-round strategy imitation to multiple rounds to better capture players' potential non-rational behavior. Using intensive simulations, we explore the effects of transition probabilities and game parameters on game transitions and cooperation. Our study finds that strategy-driven game transitions promote cooperation, and increasing the transition rates of Markov decision chains can significantly accelerate this process. By designing different Markov decision chains, these results provide simulation based guidance for practical applications in swarm intelligence, such as strategic collaboration. + oai:arXiv.org:2512.18972v1 + physics.soc-ph + cs.SI + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1016/j.apm.2025.116710 + Applied Mathematical Modelling,2025,116710 + Chaoyang Luo, Yuji Zhang, Minyu Feng, Attila Szolnoki + + + Near-field-driven Radiative Thermal Dynamics in Aperiodic Nanostructures + https://arxiv.org/abs/2512.18974 + arXiv:2512.18974v1 Announce Type: new +Abstract: Harnessing structural correlations in near-field plasmonic and polaritonic systems hold untapped potential for controlling light-matter interactions at the nanoscale. By tuning these correlations, one can reshape mode localization, coupling, and spectral distribution which are properties central to manipulating energy transport and field enhancement in nanophotonic platforms. We exploit Vogel spirals, an aperiodic geometry where a single parameter dictates spatial correlations, to show how correlation strength reshapes the modal spectrum and transient dynamics of near-field coupling. As a proof of concept, we demonstrate that aperiodic configurations outperform both uncorrelated (random) and periodic arrays in controlling near-field radiative heat-transfer dynamics. These results establish deterministic aperiodic order as a powerful platform for tailoring correlated electromagnetic responses in next-generation nanophotonic devices. + oai:arXiv.org:2512.18974v1 + physics.optics + cond-mat.mes-hall + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + M. Prado, A. Manjavacas, F. A. Pinheiro, W. J. M. Kort-Kamp + + + Various Vicsek Models with Underlying Network Characteristics + https://arxiv.org/abs/2512.19030 + arXiv:2512.19030v1 Announce Type: new +Abstract: Collective motion is a fundamental phenomenon in biological swarms. As a framework for studying synchronization in motions, the Vicsek model is simple and efficient, assuming isotropic interactions with a complete field of view. Drawing inspiration from natural swarms, we incorporate realistic constraints into the model. By analysing the interaction structures from the complex network perspective, we demonstrate that models with the homogeneous interaction rules naturally form Erdos-Renyi networks, whereas the introduction of heterogeneity leads to Barabasi-Albert networks. Furthermore, we discover that the model's synchronization is fundamentally governed by the average degree of the interaction network. Through a comparative analysis across these topologies, we identify a stretched-exponential relationship between the average degree and the synchronization metrics. + oai:arXiv.org:2512.19030v1 + physics.soc-ph + nlin.AO + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Haoshuai Wang, Zhaoqi Dong, Lei Chen + + + Enhanced Vascularity in Gelatin Scaffolds via Copper-Doped Magnesium-Calcium Silicates Incorporation: In-Vitro and Ex-Ovo Insights + https://arxiv.org/abs/2512.19055 + arXiv:2512.19055v1 Announce Type: new +Abstract: Addressing a critical challenge in current tissue-engineering practices, this study aims to enhance vascularization in 3D porous scaffolds by incorporating bioceramics laden with pro-angiogenic ions. Specifically, freeze-dried gelatin-based scaffolds were infused with sol-gel-derived powders of Cu-doped akermanite (Ca2MgSi2O7) and bredigite (Ca7MgSi4O16) at various concentrations (10, 20, and 30 wt%). The scaffolds were initially characterized for their structural integrity, biodegradability, swelling behavior, impact on physiological pH, and cytocompatibility with human umbilical vein endothelial cells (HUVECs). The silicate incorporation effectiveness in promoting vascularity was then assessed through HUVEC attachment, capillary tube formation, and ex-ovo chick embryo chorioallantoic membrane assays. The findings revealed significant improvements in both in-vitro and ex-ovo vascularity of the gelatin scaffolds upon the addition of Cu-doped akermanite. The most effective concentrations were determined to be 10 and 20%, which led to notable HUVEC metabolic activity, a well-spread morphology with extensive peripheral filopodia and lamellipodia at 10% and a cobblestone phenotype indicative of in-vivo endothelium at 20% during cell attachment, the formation of complex networks of tubular structures, and robust vascularization in chick embryo development. Moving forward, the incorporation of Cu-doped akermanite into tissue-engineering scaffolds shows great potential for addressing the limitations of vascularization, especially for critical-sized bone defects, by facilitating the controlled release of pro-angiogenic and pro-osteogenic ions. + oai:arXiv.org:2512.19055v1 + physics.med-ph + cond-mat.mtrl-sci + physics.app-ph + physics.bio-ph + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1016/j.ceramint.2024.07.369 + Ceramics International, 50 (2024) 39889-39897 + Erfan Salahinejad, Avaneesh Muralidharan, Forough Azam Sayahpour, Maryam Kianpour, Mohsen Akbarian, Daryoosh Vashaee, Lobat Tayebi + + + Non-Dichroic Enantio-Sensitive Chiroptical Spectroscopy + https://arxiv.org/abs/2512.19062 + arXiv:2512.19062v1 Announce Type: new +Abstract: Chiroptical effects using circularly polarized light produce signals that change sign when switching either molecular handedness (enantiosensitivity) or the light helicity (circular dichroism). Here, we break this enantiosensitive-and-dichroic paradigm by measuring a new type of chiroptical signal which is enantiosensitive but not dichroic. We photoionize chiral molecules using a strong laser field and detect the three-dimensional photoelectron momentum distribution. The non-dichroic, enantiosensitive asymmetry is encoded in octupolar and higher multipolar terms in the photoelectron angular distribution, which appear in multiphoton ionization with elliptically polarized fields or cross polarized two-color fields. The robustness of the enantiosensitivity with respect to the relative phase between the vectorial components of the ionizing field represents an example of symmetry protection, and opens unexplored opportunities for imaging ultrafast dynamics in chiral molecules, such as enantiosensitive photoelectron spectroscopy with bright squeezed vacuum states. + oai:arXiv.org:2512.19062v1 + physics.chem-ph physics.atom-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by-nc-sa/4.0/ - Andr\'es Ord\'o\~nez, David Ayuso, Piero Decleva, Letizia Fede, Debobrata Rajak, Yann Mairesse, Bernard Pons + Letizia Fede, Debobrata Rajak, Chris Sparling, David Ayuso, Val\'erie Blanchet, Piero Decleva, Dominique Descamps, St\'ephane Petit, Bernard Pons, Yann Mairesse, Andr\'es Ord\'o\~nez - A Concept of Two-Point Propagation Field of a Single Photon: A Way to Picometer X-ray Displacement Sensing and Nanometer Resolution 3D X-ray Micro-Tomography - https://arxiv.org/abs/2512.17863 - arXiv:2512.17863v1 Announce Type: new -Abstract: We introduce the two-point propagation field (TPPF), a real-valued, phase-sensitive quantity defined as the functional derivative of the single-photon detection probability with respect to an infinitesimal opaque perturbation placed between source and detection slits. The TPPF is analytically derived and shown to exhibit a stable, high-frequency sinusoidal structure (6.7 nm period) near the detection slit. This structure enables shot-noise-limited displacement sensing at ~15 pm precision using routinely available synchrotron fluxes and practical nanofabricated slit/comb geometries, requiring mechanical stability only over the final 0.5 mm. The same principle provides a foundation for future nanometer-resolution 3D X-ray microtomography of bulk samples, potentially resulting in a reduced radiation dose. Two conceptual strategies, a central blocker and off-axis multi-slit arrays, are estimated to lower the required incident fluence by more than one order of magnitude each, yielding combined reductions of two to three orders of magnitude with near-term detector development. The TPPF concept, originally developed in a perturbative study of single-particle propagation, thus bridges fundamental quantum measurement questions with practical high-resolution X-ray metrology and imaging. - oai:arXiv.org:2512.17863v1 + A fast, large-scale optimal transport algorithm for holographic beam shaping + https://arxiv.org/abs/2512.19072 + arXiv:2512.19072v1 Announce Type: new +Abstract: Optimal transport methods have recently established state of the art accuracy and efficiency for holographic laser beam shaping. However, use of such methods is hindered by severe $\mathcal{O}(N^2)$ memory and $\mathcal{O}(N^2)$ time requirements for large scale input or output images with $N$ total pixels. Here we leverage the dual formulation of the optimal transport problem and the separable structure of the cost to implement algorithms with greatly reduced $\mathcal{O}(N)$ memory and $\mathcal{O}(N\log N)$ to $\mathcal{O}(N^{3/2})$ time complexity. These algorithms are parallelizable and can solve megapixel-scale beam shaping problems in tens of seconds on a CPU or seconds on a GPU. + oai:arXiv.org:2512.19072v1 physics.optics + physics.atom-ph quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Andrii Torchylo, Hunter Swan, Lucas Tellez, Jason Hogan + + + Antichiral surface states and higher-order topological states based on a modified Haldane model + https://arxiv.org/abs/2512.19078 + arXiv:2512.19078v1 Announce Type: new +Abstract: Antichiral surface states, characterized by unidirectional propagation on parallel surfaces, offer unique potential for controlling classical waves. However, their realization typically relies on complex implementations of the two-dimensional modified Haldane model, limiting practical applications. Here, we propose a simplified scheme to realize such states within the nodal-line semimetal phase of a single-layer honeycomb lattice, by emulating the essential physics of the modified Haldane model through an introduced layer degree of freedom. Furthermore, we demonstrate that unequal vertical interlayer couplings can generate valley higher-order topological partial bandgaps, hosting coexisting one-dimensional hinge states and gapped antichiral surface states. We numerically verify these multiple topological states in acoustic crystals, establishing a versatile platform for advanced wave manipulation. + oai:arXiv.org:2512.19078v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Jia-Rui Xu, Zhan Xiong, Kai Deng, Hai-Xiao Wang, Shiyang Liu, Yixian Qian, Jian-Hua Jiang + + + Renormalization-Group Geometry of Homeostatically Regulated Reentry Networks + https://arxiv.org/abs/2512.19086 + arXiv:2512.19086v1 Announce Type: new +Abstract: Reentrant computation-recursive self-coupling in which a network continuously reinjects and reinterprets its own internal state-plays a central role in biological cognition but remains poorly characterized in neural network architectures. We introduce a minimal continuous-time formulation of a homeostatically regulated reentrant network (FHRN) and show that its population dynamics admit an exact reduction to a one-dimensional radial flow. This reduction reveals a dynamically fixed threshold for sustained reflective activity and enables a complete renormalization-group (RG) analysis of the reentry-homeostasis interaction. We derive a closed RG system for the parameters governing structural gain, homeostatic stiffness, and reentrant amplification, and show that all trajectories are attracted to a critical surface defined by $\gamma\rho=1$, where intrinsic leak and reentrant drive exactly balance. The resulting phase structure comprises quenched, reactive, and reflective regimes and exhibits a mean-field critical onset with universal scaling. Our results provide an RG-theoretic characterization of reflective computation and demonstrate how homeostatic fields stabilize deep reentrant transformations through scale-dependent self-regulation. + oai:arXiv.org:2512.19086v1 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Byung Gyu Chae + + + Multilevel Photonic Switching in GST-467 for Deep Neural Network Inference + https://arxiv.org/abs/2512.19105 + arXiv:2512.19105v1 Announce Type: new +Abstract: Phase-change materials (PCMs) have emerged as key enablers of non-volatile, ultra-compact photonic switches for energy-efficient deep neural network (DNN) applications. In this work, we investigate the recently discovered $\mathrm{Ge_{4}Sb_{6}Te_{7}}$ (GST-467) as a high-contrast optical PCM and demonstrate its suitability for multi-level photonic computing. The complex refractive indices of amorphous and crystalline GST-467 were experimentally extracted and used to propose a segmented silicon-on-insulator photonic switch optimized at 1550 nm. Three-dimensional FDTD simulations reveal that segmentation significantly enhances the extinction ratio while maintaining low insertion loss, resulting in a more than seven times higher design figure of merit than an unsegmented design. Laser-induced thermo-optical simulations further establish efficient, reversible switching with sub-nJ energy requirements for crystallization and amorphization. Compared with established GST, GSST, and GSS compositions, GST-467 provides the largest transmission contrast and supports up to 48 resolvable optical states. When deployed as multi-level weights in photonic DNN architectures, the GST-467 switch achieves superior classification accuracy on EMNIST and Fashion-MNIST benchmarks. These results position GST-467 as a highly promising PCM for scalable, low-energy photonic computing and neuromorphic hardware. + oai:arXiv.org:2512.19105v1 + physics.optics + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Li Hua Yu + Arpan Sur, Sudipta Saha, Chih-Yu Lee, Ichiro Takeuchi - Data-Driven Calibration of Large Liquid Detectors with Unsupervised Learning - https://arxiv.org/abs/2512.17866 - arXiv:2512.17866v1 Announce Type: new -Abstract: This paper demonstrates a novel method to extract photomultiplier tube (PMT) calibration timing constants in large liquid scintillation detectors from physics data using the machinery of unsupervised deep learning. The approach uses a simplified physical model of optical photon transport in the loss function, with PMT calibration constants treated as free parameters, and the simple assumption that individual events represent point-like emission. The problem is, thus, effectively reduced to that of regression on a very large scale, made tractable by deep learning architectures and automatic differentiation frameworks. Using data from the 9,300 PMTs in the SNO+ detector, the method has been shown to reliably extract 3 calibration constants for each of the over 7,500 online PMTs using radioactive background events. We believe that this basic approach can be straightforwardly generalised for a wide range of applications. - oai:arXiv.org:2512.17866v1 + Design, simulation and performance of the resistive-anode PICOSEC Micromegas detector + https://arxiv.org/abs/2512.19120 + arXiv:2512.19120v1 Announce Type: new +Abstract: The PICOSEC Micromegas detector is a Micro-Pattern Gaseous Detector concept developed to achieve tens of picosecond timing resolution for charged particle detection by combining a Cherenkov radiator with a two-stage Micromegas amplification structure. To improve operational robustness, a resistive anode has been implemented using a DLC layer deposited on a Kapton substrate. While this design enhances detector stability, the resistive layer may influence rate capability, signal formation, and detector capacitance, altering timing performance. + This work presents a comprehensive study of a resistive design, including an analytical model and finite-element simulations to quantify rate-dependent gain reduction due to ohmic voltage drop on the resistive layer. An analytical solution for the voltage across a finite-size resistive layer is derived, and a numerical model is developed to evaluate gain suppression under intense particle fluxes. The impact of the resistive layer on signal formation is investigated using time-dependent weighting fields and the Garfield++ simulation framework. The contribution of signal components induced by the resistive layer is quantified, and preservation of the signal leading edge is found for surface resistivities above 100 kohm per square. + Single-channel resistive-anode prototypes were designed, constructed, and experimentally characterized. Laboratory measurements using single photoelectrons and power spectral density analysis show the predicted reduction in signal amplitude while preserving the leading edge. Muon beam tests with CsI and DLC photocathodes demonstrate a time resolution of 11.5 ps for CsI, comparable to 11.9 ps for the metallic-anode device, showing the suitability of the resistive design for precision timing applications. + oai:arXiv.org:2512.19120v1 physics.ins-det - hep-ex - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Djunes Janssens, Antonija Utrobicic, Marinko Kovacic, Marta Lisowska, Eraldo Oliveri, Florian Brunbauer, Karl Floethner, Hans Muller, Rui De Oliveira, Giorgio Orlandini, Leszek Ropelewski, Lucian Scharenberg, Thomas Schneider, Miranda van Stenis, Rob Veenhof, Thomas Papaevangelou, Roy Aleksan, Stephane Aune, Thomas Gustavsson, Alexandra Kallitsopoulou, Philippe Legou, Michal Pomorski, Emmanuel Scorsone, Lukas Sohl, Mariam Kebbiri, Spyros Tzamarias, Dimos Sampsonidis, Yannis Angelis, Ioannis Maniatis, Ioannis Karakoulias, Jonathan Bortfeldt, Ilaria Vai, Matteo Brunoldi, Davide Fiorina, Paolo Vitulo, Jaydeep Datta, Nathan Shankman, Kondo Gnanvo, Klaus Dehmelt, Brian Kross, Jack McKisson, Akash Pandey, George Fanourakis, Michele Gallinaro, Francisco Garcia, Yi Zhou, Jianbei Liu, Yue Meng, Xu Wang, Zhiyong Zhang, Michael Lupberger, Yorgos Tsipolitis, Maja Mi\v{c}eti\'c, Kre\v{s}imir Salamon, Sebastian White + + + Classical and relativistic balance of configurational forces + https://arxiv.org/abs/2512.19143 + arXiv:2512.19143v1 Announce Type: new +Abstract: This article develops a unified variational framework for configurational (or material) forces in both Classical (3D, non-relativistic) and Relativistic (4D) Continuum Mechanics. Configurational forces describe the evolution of material defects-such as cracks, dislocations, and interfaces-which move relative to the material rather than through physical space. In the classical setting of hyperelasticity, the authors revisit the balance of configurational forces using an intrinsic Lagrangian formulation, where the material body is modeled as an abstract three-dimensional manifold. By treating the reference configuration as a variable and performing a Lagrangian variation with respect to it, they show that the configurational forces balance naturally emerges. Importantly, this balance equation is not independent: it is equivalent to the standard balance of linear momentum combined with constitutive relations, and it is expressed through the Eshelby stress tensor on the reference configuration. The framework is then extended to Relativistic Hyperelasticity within General Relativity. Matter is described by a matter field, a vector valued function, defined on the four-dimensional Universe, and the Lagrangian (i.e., Action) includes both matter and gravitational contributions. Two stress-energy tensors arise: the Noether stress-energy tensor (from variations with respect to the matter field) and the Hilbert stress-energy tensor (from variations with respect to the Universe metric). Assuming General Covariance, the authors prove that these tensors and their associated balance laws are equivalent. By introducing the notion of an observer and specializing to static spacetimes, the authors define a relativistic generalization of the deformation and derive a four-dimensional Eshelby tensor. They show that in Special Relativity, as in Classical Continuum Mechanics, the relativistic configurational forces balance is not a new equation but follows from the conservation laws of the Noether stress-energy tensor. Finally, they recover the classical configurational forces balance as the non-relativistic limit of the relativistic theory. Overall, the paper provides a rigorous geometric and variational interpretation of configurational forces, unifying classical and relativistic formulations and clarifying their deep connection with standard equilibrium equations. + oai:arXiv.org:2512.19143v1 + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Rodrigue Desmorat (LMPS), Anthony Gravouil (LaMCoS), Boris Kolev (LMPS) + + + Flexible Framework for Surface Hopping: From Hybrid Schemes for Machine Learning to Benchmarkable Nonadiabatic Dynamics + https://arxiv.org/abs/2512.19152 + arXiv:2512.19152v1 Announce Type: new +Abstract: Nonadiabatic molecular dynamics is a key technique for investigating a broad range of photochemical and photophysical processes. Among the established approaches, surface hopping schemes are widely used and can be easily integrated with various quantum chemistry programs or machine learning models. We present a flexible framework in MLatom that includes a newly implemented Tully's fewest-switches surface hopping algorithm and its time-dependent Baeck--An variant. The capabilities of this framework are demonstrated through three representative examples corresponding to typical stages of a surface hopping study. First, we focus on methods providing energy, energy gradients and nonadiabatic couplings. We show that the flexibility of user-defined custom models can save computational time and that it is useful for benchmarking machine learning models. Next, we compare curvature-driven surface hopping schemes and show that Landau--Zener approach outperforms the time-dependent Baeck--An scheme. Finally, we showcase easy-to-use analysis tools for both individual trajectories and trajectory ensembles. This framework enables accelerated development of machine learning models and provides deeper insight into nonadiabatic dynamics. It is available as a part of the open-source MLatom package. + oai:arXiv.org:2512.19152v1 + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Scott DeGraw, Steve Biller, Armin Reichold + Jakub Martinka, Miko{\l}aj Martyka, Biman Medhi, Ji\v{r}\'i Pittner, Pavlo O. Dral - Learning vertical coordinates via automatic differentiation of a dynamical core - https://arxiv.org/abs/2512.17877 - arXiv:2512.17877v1 Announce Type: new -Abstract: Terrain-following coordinates in atmospheric models often imprint their grid structure onto the solution, particularly over steep topography, where distorted coordinate layers can generate spurious horizontal and vertical motion. Standard formulations, such as hybrid or SLEVE coordinates, mitigate these errors by using analytic decay functions controlled by heuristic scale parameters that are typically tuned by hand and fixed a priori. In this work, we propose a framework to define a parametric vertical coordinate system as a learnable component within a differentiable dynamical core. We develop an end-to-end differentiable numerical solver for the two-dimensional non-hydrostatic Euler equations on an Arakawa C-grid, and introduce a NEUral Vertical Enhancement (NEUVE) terrain-following coordinate based on an integral transformed neural network that guarantees monotonicity. A key feature of our approach is the use of automatic differentiation to compute exact geometric metric terms, thereby eliminating truncation errors associated with finite-difference coordinate derivatives. By coupling simulation errors through the time integration to the parameterization, our formulation finds a grid structure optimized for both the underlying physics and numerics. Using several standard tests, we demonstrate that these learned coordinates reduce the mean squared error by a factor of 1.4 to 2 in non-linear statistical benchmarks, and eliminate spurious vertical velocity striations over steep topography. - oai:arXiv.org:2512.17877v1 - physics.ao-ph + Optical design and characterization of a multi-depth vision simulator + https://arxiv.org/abs/2512.19168 + arXiv:2512.19168v1 Announce Type: new +Abstract: We present a vision simulator device (Katsim), a compact near-eye optical display designed for assessing postoperative corrected vision, preoperative intraocular lens (IOL) assessment, and objective IOL characterization. The system forms a virtual image using an amplitude-modulated LCoS spatial light modulator (AM-SLM), RGB LED illumination, and a high-speed varifocal lens. In the proposed architecture, the LED illumination and varifocal lens diopter changes are triggered in synchrony with the SLM RGB subframes, rendering three depth planes perceptually simultaneously via high-frequency time-multiplexing. Operating at 60 frames per second (fps), the system achieves an effective 180 Hz depth-coded cycle, enabling sharp, multi-depth rendering within a dynamically adjustable depth range from 0.2 m to optical infinity. The system's eyebox is configurable from 1 to 5 mm, while maintaining a fixed spatial location and preserving angular magnification regardless of changes in focus or eyebox size. The designed system features a 9.15-degree field of view. An integrated infrared pupil-tracking module detects non-cataractous regions of the cataractous crystalline lens, and the projected imagery is mechanically steered through those clear zones in real time. The proposed vision simulator supports both subjective simulation of post-surgical vision for patient-specific counseling and objective optical evaluation of IOLs, including resolution and contrast fidelity (e.g., modulation transfer function, contrast transfer function, and defocus curves). By decoupling depth modulation from eyebox position and size, the system offers a modular, portable platform that supports enhanced preoperative planning, personalized IOL selection, objective IOL characterization, and use as a novel research vision tool. + oai:arXiv.org:2512.19168v1 + physics.optics + cs.SY + eess.SY + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Parviz Zolfaghari, Ehsan Varasteh, Koray Kavakli, Arda Gulersoy, Afsun Sahin, Hakan Urey + + + Real-time phase control methods for cold-atom interferometry + https://arxiv.org/abs/2512.19174 + arXiv:2512.19174v1 Announce Type: new +Abstract: We present two methods to achieve real-time inertial phase compensation in atom interferometers. Both methods, based on jumps of the position of the retroreflection mirror or frequencies of Raman lasers, demonstrate similar state-of-the-art performance on our cold atom gyroscope, comparable to that of the reference method based on optical phase jumps. These alternative approaches broaden the scope of applications for real-time inertial phase compensation methods in atomic interferometers, particularly for space applications. + oai:arXiv.org:2512.19174v1 + physics.atom-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Mohamed Guessoum (SYRTE, LNE - SYRTE, LTE), Nathan Marliere (SYRTE, LNE - SYRTE, LTE), Charbel Cherfan (SYRTE, LNE - SYRTE, LTE), Remi Geiger (SYRTE, LNE - SYRTE, LTE), Arnaud Landragin (SYRTE, LNE - SYRTE, LTE) + + + Photonic Spiking Graph Neural Network for Energy-Efficient Structured Data Processing + https://arxiv.org/abs/2512.19182 + arXiv:2512.19182v1 Announce Type: new +Abstract: Photonic computing shows great potential for signal processing and artificial intelligence (AI) acceleration due to its ultra-high speed, low energy consumption, and inherent parallelism. Existing photonic computing research has mainly focused on convolutional neural networks (CNNs) and fully connected neural networks (FCNNs), which are well suited for tasks such as image classification and object detection but face limitations in handling graph-structured data. Graph neural networks (GNNs) are specifically designed to model complex relational structures. In this work, we propose a photonic spiking graph neural network (PSGNN) architecture that integrates the structural modeling capability of GNNs, the temporal dynamics of spiking neurons, and the parallel computing advantages of photonic hardware. Through hardware-software co-optimization, a bias-term simulation method tailored for photonic chips is implemented using feature-dimension expansion, enabling effective network training. Experiments on the KarateClub and PubMed datasets achieve training accuracies of 100 percent (92 +/- 2 percent) and test accuracies of 97 percent (90 +/- 1 percent). A silicon photonics 4 x 4 Mach-Zehnder interferometer (MZI) array is further constructed for hardware validation, achieving a test accuracy of 93 percent. The system demonstrates an inference latency of 97 ps, with an energy efficiency of 280 GOPS/W and a computational density of 52 GOPS/mm^2. These results highlight the potential of PSGNN for structured-data processing applications. + oai:arXiv.org:2512.19182v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Wanting Yu, Shuiying Xiang, Xingxing Guo, Shangxuan Shi, Haowen Zhao, Xintao Zeng, Yahui Zhang, Hongbo Jiang, Yue Hao + + + Deformation and Stress Evolution during Laser Powder Bed Fusion of Semi-Crystalline Polyamide-12 + https://arxiv.org/abs/2512.19188 + arXiv:2512.19188v1 Announce Type: new +Abstract: Laser powder bed fusion (L-PBF) of semi-crystalline polymers such as polyamide-12 (PA12) has found increasing use in various industrial applications. However, achieving high dimensional accuracy remains a significant challenge. Despite the seemingly straightforward layer-by-layer manufacturing concept, the L-PBF process involves complex thermal histories and strongly coupled multiphysics, making the evolution of stress and deformation mechanisms still not fully understood. To address this, a comprehensive three-dimensional thermo-mechanical modeling framework is developed to simulate the L-PBF process of PA12. The model for the first time incorporates transient heat transfer, phase transformation induced volumetric shrinkage, thermoviscoelasticity, and a modified non-isothermal crystallization kinetics. To alleviate the computational burden of part-scale simulations, a dual-mesh strategy is employed to efficiently couple thermal and mechanical fields without compromising numerical accuracy, which also enables the framework to handle L-PBF simulations of arbitrarily complex three-dimensional geometries. Particular attention is paid to the role of mechanical and thermal boundary conditions. Specifically, the underlying powder bed is modeled as a fictitious viscous medium, providing support while permitting upward displacement. Additionally, a radiative heat loss boundary condition, which more closely approximates the actual physical process, is applied to the top powder surface. The incorporation of this radiation effect significantly enhances the crystallization rate and improves the agreement with experimentally measured warpage. The model is validated against experimental warpage data under various preheating temperatures. Furthermore, strain decoupling analysis for the first time reveals that displacement induced by phase transformation is approximately 10 times greater than that caused by thermal expansion, highlighting the dominant role of crystallizationinduced shrinkage in warpage formation. Numerical tests also indicate that warpage is highly sensitive to the preheating target temperature of the PA12 powder bed, while the temperature of the newly recoated powder within the tested range has a limited effect. This work provides a predictive modeling foundation for future optimization of polymer L-PBF processes at part-scale, particularly in controlling deformation and improving dimensional accuracy. + oai:arXiv.org:2512.19188v1 + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Additive Manufacturing, 2025 + Zhongfeng Xu (CEMEF), Wei Zhu (CEMEF), Lionel Freire (CEMEF), No\"elle Billon (CEMEF), Jean-Luc Bouvard (CEMEF), Yancheng Zhang (CEMEF) + + + Strong actuation and optomechanical application of mass loaded membranes + https://arxiv.org/abs/2512.19191 + arXiv:2512.19191v1 Announce Type: new +Abstract: An increasing number of studies are moving towards the combination of quantum mechanics and gravity, where studying gravity from a very small source mass is a viable starting point. Preparing for such experiments, investigations of weak gravitational forces have employed mechanical resonators to detect time-dependent gravitational forces from actuated source masses. Here, we demonstrate a source mass approach which utilizes capacitive actuation of a 1 mg gold sphere embedded on a silicon nitride membrane, rather than piezoelectric or motorized actuation. The design simultaneously provides a method for microwave optomechanical implementation by coupling the membrane position to the electromagnetic mode of a 3D cavity. The cavity quality factor is not significantly compromised by electromagnetic leakage to the actuation electrode, allowing DC and kilohertz AC voltages to be introduced in the region where electric fields are strongly concentrated. We measure over 700 nm of driven oscillation amplitude and more than ten percent tunability in the mechanical resonance frequency of the loaded membrane, giving the potential to match the oscillations to the frequency range of a detector in future experiments. An optomechanical readout is demonstrated by measuring the cavity resonance at cryogenic temperatures, while room temperature measurements provide complimentary understanding of the mechanisms which influence the mechanical response, including repulsive contact due to collisions within the device. + oai:arXiv.org:2512.19191v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Joe Depellette, Ewa Rej, Richa Cutting, Mika A. Sillanp\"a\"a + + + Far- and near-field photon noise limits to the detectivity of nanometer-thick thermal detectors + https://arxiv.org/abs/2512.19192 + arXiv:2512.19192v1 Announce Type: new +Abstract: Thermal-radiation detectors such as bolometers -- often found as thin, suspended films -- are intrinsically limited by their optical absorption properties and by their intrinsic thermal conductive and radiative losses. We analyze the impact of the photon energy exchange between the film and a substrate located close to each other, noticing that the associated near-field exchange has been overlooked and could reduce the detectivity. In addition, we study how the nanometric thickness of the suspended film and its material impact the detectivity of such sensors. It is found that the blackbody-related photon noise limit of the detectivity can be surpassed with thin films. These results emphasize pathways for improvements of thermal-radiation detectors. + oai:arXiv.org:2512.19192v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Olivier Merchiers (CETHIL, INSA Lyon), Aapo Varpula (VTT), Kirsi Tappura (VTT), Pierre-Olivier Chapuis (CETHIL), Mika Prunnila (VTT) + + + Self-Consistent Probability Flow for High-Dimensional Fokker-Planck Equations + https://arxiv.org/abs/2512.19196 + arXiv:2512.19196v1 Announce Type: new +Abstract: Solving high-dimensional Fokker-Planck (FP) equations is a challenge in computational physics and stochastic dynamics, due to the curse of dimensionality (CoD) and the bottleneck of evaluating second-order diffusion terms. Existing deep learning approaches, such as Physics-Informed Neural Networks (PINNs), face computational challenges as dimensionality increases, driven by the $O(D^2)$ complexity of automatic differentiation for second-order derivatives. While recent probability flow approaches bypass this by learning score functions or matching velocity fields, they often involve serial computational operations or depend on sampling efficiency in complex distributions. To address these issues, we propose the Self-Consistent Probability Flow (SCPF) method. We reformulate the second-order FP equation into an equivalent first-order deterministic Probability Flow ODE (PF-ODE) constraint. Unlike score matching or velocity matching, SCPF solves this problem by minimizing the residual of the PF-ODE continuity equation, which avoids explicit Hessian computation. We leverage Continuous Normalizing Flows (CNF) combined with the Hutchinson Trace Estimator (HTE) to reduce the training complexity to linear scale $O(D)$, achieving an effective $O(1)$ wall-clock time on GPUs. To address data sparsity in high dimensions, we apply a generative adaptive sampling strategy and theoretically prove that dynamically aligning collocation points with the evolving probability mass is a necessary condition to bound the approximation error. Experiments on diverse benchmarks -- ranging from anisotropic Ornstein-Uhlenbeck (OU) processes and high-dimensional Brownian motions with time-varying diffusion terms, to Geometric OU processes featuring non-Gaussian solutions -- demonstrate that SCPF effectively mitigates the CoD, maintaining high accuracy and constant computational cost for problems up to 100 dimensions. + oai:arXiv.org:2512.19196v1 + physics.comp-ph cs.LG - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + cs.NA + math.NA + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by/4.0/ - Tim Whittaker, Seth Taylor, Elsa Cardoso-Bihlo, Alejandro Di Luca, Alex Bihlo + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xiaolong Wu, Qifeng Liao - Inverse-Designed Phase Prediction in Digital Lasers Using Deep Learning and Transfer Learning - https://arxiv.org/abs/2512.17879 - arXiv:2512.17879v1 Announce Type: new -Abstract: Digital lasers control the laser beam by dynamically updating the phase patterns of the spatial light modulator (SLM) within the laser cavity. Due to the presence of nonlinear effects, such as mode competition and gain saturation in digital laser systems, it is often necessary to rely on specifically manually tailored approach or iteration processes to find suitable loaded phases in Digital lasers. This study proposes a model based on Conditional Generative Adversarial Networks (cGAN) and a modified U-Net architecture, with designed loss functions to inverse design the loaded phases. In this work, we employ deep neural networks to learn the nonlinear effects in simulated L-shape digital lasers, enabling the prediction of SLM-loaded phases for both analytical and non-analytical arbitrary structured light fields. The results demonstrate superior performance on non-analytical light fields compared to the current methods in L-shape Digital lasers. Furthermore, a transfer learning strategy is introduced, allowing knowledge obtained from one class of structured beams to be effectively reused for another, thereby enhancing generalization and improving performance under limited training data. Importantly, this method, the first proposed learning framework for digital lasers, is not limited to the L-shaped digital lasers discussed in this study, providing an efficient alternative for generating structured light in other digital laser systems. - oai:arXiv.org:2512.17879v1 + Highly efficient multi-chromatic Raman microlasers from cavity polygon modes on thin-film lithium niobate platform + https://arxiv.org/abs/2512.19205 + arXiv:2512.19205v1 Announce Type: new +Abstract: The integration of stimulated Raman scattering (SRS) and second order nonlinearity in non-centrosymmetric photonic microresonators presents a highly promising solution for developing on-chip coherent light sources with exceptional bandwidth and flexible tunability. Our study introduces an innovative methodology leveraging cavity polygon modes within an X-cut thin-film lithium niobate microdisk to achieve highly efficient multi-chromatic Raman microlasers. Specifically, high-Q square modes characterized by two parallel sides oriented perpendicularly relative to the optical axis of lithium niobate crystal were excited. These modes offer distinct advantages, including enhancing both mode-field overlap and improved phase matching, achieved through the utilization of the largest second-order susceptibility component (d_33), which is critical for Raman-quadratic nonlinear interactions. The experimental results highlight significant advancements in multi-wavelength multi-wavelength laser generation, with forward stimulated Raman laser signals exhibiting a high conversion efficiency of up to 65.02% and an impressively narrow integral linewidth of only 5.2 kHz. Simultaneously, our system enables the generation of multi-wavelength Raman-quadratic laser signals across the ~800 nm and ~530 nm spectral bands. These findings are further underscored by an impressive absolute conversion efficiency of 1.33% for the 797.4-nm Raman laser, achieved at a remarkably low pump power of just 1.07 mW. This work not only extends the application scope of cavity polygon modes from single second/third-order nonlinear optical processes to cascaded processes but also establishes a foundation for realizing high-efficiency on-chip multi-chromatic laser sources with versatile functionalities. + oai:arXiv.org:2512.19205v1 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-sa/4.0/ + Yixuan Yang, Chuntao Li, Renhong Gao, Yingnuo Qiu, Lingling Qiao, Jielei Ni, Jintian Lin, Ya Cheng + + + Magnetically confined charged particles: From steep density profiles to the breaking of the adiabatic invariant + https://arxiv.org/abs/2512.19211 + arXiv:2512.19211v1 Announce Type: new +Abstract: This study examines the stability of Vlasov equilibrium solutions for magnetically confined plasmas, derived through the principle of maximum entropy. By treating the toroidal limit as a perturbation from an analytical cylindrical solution, we demonstrate that these equilibria align well with the inviscid magnetohydrodynamic (MHD) description. Using the aspect ratio as a perturbation parameter, we compute particle trajectories sampled from the kinetic equilibrium distribution, confirming the overall stability of the solutions. However, under burning plasma conditions, chaotic dynamics emerge for particles with supra-thermal and even thermal energies. This destroys the adiabatic invariance of the magnetic moment. The exact consequences are unclear, but they could undermine the foundational assumptions of gyrokinetic modelling in burning plasmas. Nevertheless, these results suggest the possibility of unaccounted transport losses in future burning plasma operations. The interplay between turbulence and energetic particles in the presence of Hamiltonian chaos certainly warrants further investigation. + oai:arXiv.org:2512.19211v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Yu-Che Wu, Kuo-Chih Chang, Shu-Chun Chu + Aur\'elien Cordonnier (CPT), Yohann Lebouazda (CPT), Xavier Leoncini (CPT), Guilhem Dif-Pradalier (IRFM) - Tuna-Like Swimmers Experience a Fluid-Mediated Stable Side-by-Side Formation - https://arxiv.org/abs/2512.17888 - arXiv:2512.17888v1 Announce Type: new -Abstract: New free-swimming experiments and simulations are conducted on a pair of three-dimensional, bio-robotic swimmers composed of a body and tail section based on Yellowfin tuna, Thunnus albacares. It is discovered that the pair converges spontaneously to a side-by-side schooling formation that is stable to perturbations in the swimming direction at a fixed lateral spacing. We reveal that for close lateral spacings of 43% of the body length and thick, tuna-like bodies with a 22% thickness-to-length ratio, the flow between the swimmers is accelerated in a "channeling effect" due to flow constriction. Consequently, this creates a low-pressure zone that is the primary mechanism generating a fluid-mediated restorative force, thereby making the side-by-side formation hydrodynamically stable. This quasi-steady mechanism makes the stability of the formation insensitive to the phase synchronization between the bio-robots in contrast to previous results for schooling foils. Moreover, in the side-by-side formation tunalike swimmers are seen to have only a small reduction in their swimming speed and a concurrent small rise in their cost of transport. By leveraging this channeling effect, bio-robotic schools may be able to maintain a schooling formation with little or no control. This flow mechanism may also be present in biological schools of tuna-like fish where it may sculpt the formations observed in nature. - oai:arXiv.org:2512.17888v1 + Formation of external particle jets on a spherical particle bed subjected to strong explosive loading + https://arxiv.org/abs/2512.19241 + arXiv:2512.19241v1 Announce Type: new +Abstract: We report the mechanism for the formation of external particle jets on a spherical particle bed subjected to strong explosive loading, revealing a critical dependence on particle size. Under strong explosive loading, the formation of external particle jets is primarily driven by a drag-coupled mechanism. We conducted Eulerian-Lagrangian simulations, with up to $2048^3$ effective cells and $1.8$ million tracked parcels on an adaptive mesh, for both small- and large-particle cases. Pronounced jets are observed only with small particles, alongside accelerated bed thickening. By defining characteristic inner and outer radii, the particle bed thickness evolution is quantified, showing an initial linear growth followed by a nonlinear deceleration. Particle dynamics analysis indicates that drag force dominates particle motion and jet formation during the nonlinear stage. The initial angular non-uniformity of the particle bed induces a non-uniform gas radial velocity. Through drag coupling, this flow asymmetry generates a radial velocity difference in small particles, thereby promoting pronounced jet formation, whereas large particles resist this drag-induced effect. The greater drag-induced deceleration on smaller particles leads to an increased velocity difference across the particle bed, explaining the accelerated thickening. A characteristic radius model that integrates the Gurney model for the linear stage with a drag-dominated deceleration model for the nonlinear stage is established and shows good agreement with numerical results across different particle sizes. + oai:arXiv.org:2512.19241v1 physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 new - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Pedro C. Ormonde, Matthew Stasolla, Alec Menzer, Joseph Zhu, Hilary Bart-Smith, Haibo Dong, Keith W. Moored + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yifeng He, Junsheng Zeng, Baolin Tian, Yue Yang - Spectro-temporal unitary transformations for coherent modulation: design trade-offs and practical considerations - https://arxiv.org/abs/2512.17890 - arXiv:2512.17890v1 Announce Type: new -Abstract: This paper analyzes the performance of spectro-temporal unitary transforms for coherent optical modulation. Unlike conventional IQ modulation, such transforms are based on a cascade of phase modulators and dispersive elements, so are theoretically lossless and not limited by the bandwidth of the constituent modulators. We analyse the performance limits and design trade-offs of this scheme: estimating how the number of stages, amount of dispersion, modulator bandwidth, symbol block length and electrical signal power impacts the achievable signal-to-distortion ratio (SDR). Importantly, we show that high (>30 dB) SDRs suitable for modern >200 GBd class coherent optical communications are achievable with a low (<6) number of stages and reasonable parameters for driver power, modulator bandwidth and on-chip dispersion. Finally we address the SDR penalties associated with potential phase, amplitude, or dispersion errors, and limited DAC resolution. - oai:arXiv.org:2512.17890v1 + Optical parametric free-electron--photon quantum interaction + https://arxiv.org/abs/2512.19255 + arXiv:2512.19255v1 Announce Type: new +Abstract: Optical parametric processes underpin quantum photonics, while free-electron--photon interactions offer agile pathways to generate nontrivial quantum photonic states. These threads have so far largely progressed independently, whereas placing free electrons in a driven nonlinear system can potentially activate coherent parametric interaction channels for joint state engineering of both types of particles. Here we unify these paradigms by developing a general theoretical framework for parametric free-electron--photon interactions in a nonlinear optical system driven by degenerate parametric down-conversion. Unlike free electrons in a linear bath, here they can couple to Bogoliubov quasiparticles through two detuned phase-matching channels, where the parametric process and free-electron interactions can quantum amplify each other. Seeding the interaction with squeezed vacuum yields gain-only or loss-only electron energy spectra, and enables electron-heralded squeezed Fock states; with bare vacuum, postselecting electron energy sidebands generates high-fidelity Schr\"odinger cat states. Our results show how optical parametric interactions can quantum shape free electrons and photons, potentially enabling a quantum parametric dielectric laser accelerator that mitigates the need for temporal phase synchronization, thereby allowing acceleration probabilities to approach unity even for phase-random electrons. + oai:arXiv.org:2512.19255v1 physics.optics - eess.SP - Mon, 22 Dec 2025 00:00:00 -0500 + cond-mat.mes-hall + physics.acc-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 new http://creativecommons.org/licenses/by/4.0/ - Callum Deakin, Xi Chen + Zetao Xie, Zehai Pang, Yi Yang - Characteristic features of the resonant trident process in the field of a strong monochromatic electromagnetic wave - https://arxiv.org/abs/2512.16951 - arXiv:2512.16951v1 Announce Type: cross -Abstract: The characteristic features of the resonant trident process (Oleinik resonances) have been theoretically studied in a wide range of frequencies and intensities of a circularly polarized strong electromagnetic wave. The resonant trident process is defined by two characteristic quantum energies: the characteristic energy of the nonlinear Compton effect and the characteristic energy of the nonlinear Breit-Wheeler process. These characteristic energies depend significantly on the frequency and intensity of the wave, as well as on the angle between the momenta of the initial electrons and the electromagnetic wave. The resonant trident process is effective when the energy of the initial electrons is greater than or on the order of magnitude of the corresponding characteristic energies. It is shown that quantum entanglement of final particles takes place in this resonant process. An important aspect of the resonant trident process is the equality of the energies of the electron and positron pairs. Analytical expressions for the differential rates of the resonant trident process on the energy of final particles are obtained. The corresponding analytical expressions for full rates have also been obtained. It is shown that the rate data of the resonant trident process in the field of optical and X-ray wave frequencies significantly exceed the corresponding rate of the non-resonant trident process. Results obtained can be used in experiments at leading laser centers, as well as to explain QED processes in strong X-ray fields near neutron stars and magnetars. - oai:arXiv.org:2512.16951v1 - hep-ph - physics.plasm-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Precise control of high-frequency ultrasounds in thin crystals for the development of tunable narrowband and directional gamma-ray sources + https://arxiv.org/abs/2512.19268 + arXiv:2512.19268v1 Announce Type: new +Abstract: This work presents a complete methodology for the precise characterization of the acoustic field inside crystal-based devices driven by high-frequency ultrasounds towards the generation of tunable narrowband and directional gamma radiation via undulation of ultra-relativistic charged particles. Such gamma-ray sources have long been anticipated by the scientific community, as they promise new powerful tools for the study of high-energy physical phenomena and the development of novel nuclear technologies. In such devices, a piezoelectric transducer induces tens of MHz harmonic waves inside a silicon monocrystal. Ultra-relativistic charged particles traversing the crystal get trapped within the channels formed by the extremely strong electric fields of the acoustically modulated lattice planes, undergoing undulation and emitting gamma radiation. Precise characterization of the acoustic field in the crystal is crucial for the determination of the expected characteristics of the secondarily generated gamma rays. For this purpose, fast laser refraction imaging is used here to image the acoustic waves by exploiting the spatial redistribution of a laser beam optical intensity caused by the acoustic field. A dedicated computational model is developed for the estimation of the spatial distribution of the pressure and lattice deformation inside the crystal. This methodology provides a framework for future novel gamma-ray sources in high-energy facilities. + oai:arXiv.org:2512.19268v1 + physics.acc-ph + physics.app-ph + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - S. P. Roshchupkin, M. V. Shakhov + 10.1121/10.0039880 + Emmanouil Kaniolakis-Kaloudis, Nektarios Papadogiannis, Yannis Orphanos, Makis Bakarezos, Konstantinos Kaleris - Subsystems (in)dependence in GIE proposals - https://arxiv.org/abs/2512.17024 - arXiv:2512.17024v1 Announce Type: cross -Abstract: Recent proposals suggest that detecting entanglement between two spatially superposed masses would establish the quantum nature of gravity. However, these gravitationally induced entanglement (GIE) experiments rely on assumptions about subsystem independence. We sharpen the theoretical underpinnings of such proposals by examining them through the lens of algebraic quantum field theory (AQFT), distinguishing distinct operational and algebraic notions of independence. We argue that state and measurement independence of subsystems, essential to the experimental logic, is nontrivial in the presence of gauge constraints and gravitational dressing. Using gravitationally dressed fields, we recall that commutation relations between spacelike separated observables are nontrivial, undermining strict Hilbert space factorization. We further explore the implications for entanglement witnesses, investigating the Tsirelson bound when subsystem algebras fail to commute, and showing that the Tsirelson bound persists for a suitably symmetrized CHSH observable even though the operational status of such "joint" observables becomes delicate when commensurability fails. Our analysis highlights how even within linearized covariant quantum gravity, violations of microcausality may affect both the interpretation, modelling, and design of proposed laboratory tests of quantum gravity, despite remaining negligible for current experimental regimes. Although we consider GIE-style protocols as a concrete case study, the subsystem-independence issues we highlight are generic to low-energy (perturbative) quantum gravity. Finally, we derive estimates for dressing-induced microcausality violations, which suggest a complementary avenue to current proposals: in principle, bounding dressing-induced microcausality violations themselves as a probe of the quantum nature of gravity. - oai:arXiv.org:2512.17024v1 - quant-ph - hep-th - math-ph - math.MP - physics.hist-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Unifying formalism and closures for coarse-grained approaches to turbulence + https://arxiv.org/abs/2512.19274 + arXiv:2512.19274v1 Announce Type: new +Abstract: We propose the use of an unifying paradigm for the assessment and development of closed forms of the coarse-grained Navier-Stokes equations in approaches ranging from the statistical to the scale-resolving ones. It consists in the exact formalism provided by the temporally filtered Navier-Stokes equations. The fundamental idea is that the smoothing action of turbulent stresses can be described as a temporal filtering operator implicitly applied to the solution. Contrary to the average and spatial filtering operators, the temporal filter is an unifying operator smoothly varying within the statistical and scale-resolving realms. The potential of the temporal filtering paradigm is here highlighted by unveiling relevant algebraic properties and by deriving a new class of turbulence closures. A dynamic procedure is derived and shown to provide an unifying closure for both scale-resolving and statistical approaches. Results show that an improved physics is captured. Challenging phenomena such as the laminar to turbulence transition and the dependence of separation and reattachment on free-stream turbulence applied through boundary conditions are captured. + oai:arXiv.org:2512.19274v1 + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Nicolas Boulle, Guilherme Franzmann + A. Cimarelli, N. Marras, B. Niceno, Y. Tessier Urrecha + + + Optimal operating parameters for next-generation xenon gas time projection chambers + https://arxiv.org/abs/2512.19290 + arXiv:2512.19290v1 Announce Type: new +Abstract: The next-generation of neutrinoless double beta decay ($0\nu\beta\beta$) searches are targeting half-life sensitivities towards 10$^{27}$--10$^{28}$ years. Gaseous xenon time projection chamber (GXeTPC) detectors are a technology that may be able to meet this challenge due to their excellent background rejection power, scalability, and energy resolution. This paper explores how the design choices of a next-generation GXeTPC time projection chamber can impact the overall performance of the experiment. We study the performance of systems using xenon enriched in the isotope $^{136}$Xe or natural xenon, focusing on scenarios that incorporate one tonne of source isotope. The detector size, copper shielding mass, energy resolution, pressure, and diffusion amount are surveyed to evaluate the overall performance dependencies on these parameters. A detector optimized for using enriched xenon is preferred, with a factor of 10 lower background rate, driven by the large intrinsic backgrounds introduced by the copper shielding used in the detector. The performance of three types of gas TPC technologies was also explored based on different gas additives used to reduce diffusion to different levels. For all TPC technologies, we find background rates of a fraction of a count per tonne year in the region of interest are achievable. These performances are contingent on suitable energy resolution and event position placement in the drift direction being achieved for the specific detector technology. When factoring in the considerations for the construction of the detector in addition to the selection performance, there is no clear optimum pressure, with advantages and disadvantages if a high or low pressure default configuration is chosen. + oai:arXiv.org:2512.19290v1 + physics.ins-det + hep-ex + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + K. Mistry, D. R. Nygren + + + Generation of near GeV protons by tightly focused laser interacting with down-ramp density plasma + https://arxiv.org/abs/2512.19341 + arXiv:2512.19341v1 Announce Type: new +Abstract: Enhancing proton energy is of great importance in laser-driven proton acceleration with finite laser energy for applications such as cancer therapy. We demonstrate an unusual acceleration scheme that achieves higher proton energies at lower laser energies by reducing the focal spot size. Through particle-in-cell simulations and theoretical modeling, we find that at small spot sizes (0.8 {\mu}m), the proton energy is enhanced by 83.5%, much higher than that under conventional spot sizes (3 {\mu}m). This is because the proton acceleration is dominated by electrons driven by an enhanced ponderomotive force at small spot sizes, generating stronger charge-separation fields that propagate faster. To further improve the proton energy, we analytically derive an optimal electron density profile, which enables phase-stable proton acceleration with an energy increased by 60%. These results are robust across parameter variations, suggesting that advanced focusing techniques and optimal plasma profiles could loose the requirement of laser energy, potentially reducing the dependence on large-scale laser facilities for medical and scientific applications. + oai:arXiv.org:2512.19341v1 + physics.plasm-ph + physics.acc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Guanqi Qiu, Qianyi Ma, Dongchi Cai, Deji Liu, Yinren Shou, Zheng Gong, Jinqing Yu, Xueqing Yan - Comparing Homodyne and Heterodyne Tomography of Quantum States of Light - https://arxiv.org/abs/2512.17031 - arXiv:2512.17031v1 Announce Type: cross -Abstract: Non-Gaussian quantum states are critical resources in photonic quantum information processing, rendering their generation and characterization of increasing importance in quantum optics. In this work, we theoretically and numerically analyze the relative efficiency of homodyne versus heterodyne measurements for reconstructing non-Gaussian states, a major outstanding question in continuous-variable tomography. Combining a Fisher information-based formalism with simulated experiments, we find homodyne tomography to outperform heterodyne measurements for all non-Gaussian states tested, although the separation between the two modalities proves significantly narrower than suggested by the asymptotic Cramer-Rao lower bound. Our results should find use for optimizing measurement strategies in practical continuous-variable quantum systems. - oai:arXiv.org:2512.17031v1 + Talking with a ghost: semi-virtual coupled levitated oscillators + https://arxiv.org/abs/2512.19358 + arXiv:2512.19358v1 Announce Type: new +Abstract: Mesoscopic particles levitated by optical, electrical or magnetic fields act as mechanical oscillators with a range of surprising properties, such as tuneable oscillation frequencies, access to rotational motion, and remarkable quality factors. Coupled levitated particles display rich dynamics and non-reciprocal interactions, with applications in sensing and the exploration of non-equilibrium and quantum physics. In this work, we present a single levitated particle displaying coupled-oscillator dynamics by generating an interaction with a virtual or ``ghost'' particle. This ghost levitated particle is simulated on an analogue computer, and hence its prperties can be dynamically varied. Our work represents a new angle on measurement-based bath engineering and physical simulation, and in the future could lead to the generation of novel cooling mechanisms and complex physical simulation. + oai:arXiv.org:2512.19358v1 + physics.ins-det quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Ronghao Yin, Yugang Ren, Deok Young Seo, Anoushka Sinha, Jonathan D. Pritchett, Qiongyuan Wu, James Millen + + + A deterministic approach for integrating an emitter in a nanocavity with subwavelength light confinement + https://arxiv.org/abs/2512.19372 + arXiv:2512.19372v1 Announce Type: new +Abstract: We introduce a novel light-matter interface that integrates a nanoscale buried heterostructure emitter into a dielectric bowtie cavity, co-localising the optical hotspot and the electronic wavefunction. This platform enables strong light-matter interaction through deep subwavelength confinement while remaining compatible with scalable fabrication. We show that in this regime an explicit treatment of the emitter's spatial extent is required, and that a confinement-factor approximation more accurately predicts the coupling, revealing design rules inaccessible to dipole-based metrics. For an InP/InGaAsP system, we predict coupling strengths of 0.4-0.7 meV for gap sizes of 50-10 nm, establishing the buried heterostructure-bowtie architecture as a practical route to deterministic strong coupling in solid-state nanophotonics. + oai:arXiv.org:2512.19372v1 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 - cross + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Valdemar Bille-Lauridsen, Rasmus Elleb{\ae}k Christiansen, Yi Yu, Jesper M{\o}rk + + + Finding the best density functionals for water: benchmarking the forces + https://arxiv.org/abs/2512.19375 + arXiv:2512.19375v1 Announce Type: new +Abstract: A DFT benchmark on water including more than 50 functionals from GGA to double-hybrid levels is reported. The main metric is the accuracy of forces, allowing better structural coverage, higher statistical confidence, and fewer error sources compared to conventional benchmarks. The input structures include water clusters of 4~128 molecules, with highly varied yet realistic configurations of water, ice, and their mixtures. The B97M-V, {\omega}B97M-V, and revDOD-PBEP86-D4 functionals are found to be best on the mGGA, hybrid, and double-hybrid levels, respectively. No satisfying GGA functionals are found, but it can be obtained by combining BLYP-D4 with a simple correction to O-H bonds, achieving accuracy comparable to B97M-V. + oai:arXiv.org:2512.19375v1 + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Shifan Cui + + + A Critical Assessment of Pattern Comparisons Between POD and Autoencoders in Intraventricular Flows + https://arxiv.org/abs/2512.19376 + arXiv:2512.19376v1 Announce Type: new +Abstract: Understanding intraventricular hemodynamics requires compact and physically interpretable representations of the underlying flow structures, as characteristic flow patterns are closely associated with cardiovascular conditions and can support early detection of cardiac deterioration. Conventional visualization of velocity or pressure fields, however, provides limited insight into the coherent mechanisms driving these dynamics. Reduced-order modeling techniques, like Proper Orthogonal Decomposition (POD) and Autoencoder (AE) architectures, offer powerful alternatives to extract dominant flow features from complex datasets. This study systematically compares POD with several AE variants (Linear, Nonlinear, Convolutional, and Variational) using left ventricular flow fields obtained from computational fluid dynamics simulations. We show that, for a suitably chosen latent dimension, AEs produce modes that become nearly orthogonal and qualitatively resemble POD modes that capture a given percentage of kinetic energy. As the number of latent modes increases, AE modes progressively lose orthogonality, leading to linear dependence, spatial redundancy, and the appearance of repeated modes with substantial high-frequency content. This degradation reduces interpretability and introduces noise-like components into AE-based reduced-order models, potentially complicating their integration with physics-based formulations or neural-network surrogates. The extent of interpretability loss varies across the AEs, with nonlinear, convolutional, and variational models exhibiting distinct behaviors in orthogonality preservation and feature localization. Overall, the results indicate that AEs can reproduce POD-like coherent structures under specific latent-space configurations, while highlighting the need for careful mode selection to ensure physically meaningful representations of cardiac flow dynamics. + oai:arXiv.org:2512.19376v1 + physics.flu-dyn + cs.LG + Tue, 23 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Rhea P. Fernandes, Andrew J. Pizzimenti, Christos N. Gagatsos, Joseph M. Lukens + Eneko Lazpita, Andr\'es Bell-Navas, Jes\'us Garicano-Mena, Petros Koumoutsakos, Soledad Le Clainche - Immigrant Residential Segregation in Europe: A Comparative Study of Spatial Segregation Patterns in Urban Areas across 30 Countries - https://arxiv.org/abs/2512.17037 - arXiv:2512.17037v1 Announce Type: cross -Abstract: Immigrant residential segregation can profoundly shape access to opportunities, immigrant integration, and inter-group relations. Yet we lack systematic evidence on how segregation varies across Europe, and what structural factors are associated with these patterns. This study addresses the gap by focusing on two questions: (i) how does immigrant-native segregation vary across urban areas in Europe, and (ii) which urban area- and country-level characteristics are consistently linked to segregation? Using harmonised 1x1 km grid-level data from the 2021/22 census, we calculate spatially weighted Dissimilarity Indices for all 717 Functional Urban Areas (FUAs) across 30 European countries. We combine these measures with rich data on demographics, the economy, housing, immigrant populations, and policy. To identify robust correlates of segregation, we apply a Specification Curve Analysis across 16,164 regression models. Segregation is higher in Western and Northern Europe compared to most of Eastern and Southern Europe. Moreover, we show that segregation is heavily driven by macro-spatial dynamics between diverse urban cores and relatively homogeneous suburban areas. At the urban area level, segregation is systematically linked to the demographic composition and spatial distribution of the local population, economic conditions, housing market characteristics, as well as the composition of the immigrant population. At the national level, established immigrant destinations are more segregated, while migration and integration policies are not consistently linked to segregation. These findings offer the most comprehensive comparative assessment of immigrant segregation across Europe to date, revealing how structural conditions relate to spatial integration. - oai:arXiv.org:2512.17037v1 - econ.GN - physics.soc-ph - q-fin.EC - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Sculpting ultrafast mid-infrared light for solid-state high harmonic generation + https://arxiv.org/abs/2512.19412 + arXiv:2512.19412v1 Announce Type: new +Abstract: The ability to sculpt light in space, time, and polarization has revolutionized studies of light-matter interaction and enabled breakthroughs in optical communication, imaging, and ultrafast science. Among the many degrees of freedom of light, orbital angular momentum (OAM) further expands these capabilities by unlocking new regimes of control in information encoding, particle manipulation, and symmetry-driven selection rules. However, exploiting OAM to drive nonlinear, non-perturbative effects in solids remains challenging, especially in the mid-infrared (MIR) spectral regime, a key region for accessing these effects in ambient air, where spatial light modulators do not operate. Here, we circumvent this limitation by generating femtosecond, few-cycle MIR Bessel-Gauss vortex (BGV) and Perfect optical vortices (POVs), using a robust, static spatial-shaping strategy. Using those beams to drive the high-harmonic generation (HHG) process in solids, we show that the resulting harmonic beams faithfully inherit the structural properties of the drivers: the constant-intensity ring of the POV is preserved across harmonic orders, while the harmonic BGVs retain their intrinsic TC-dependent profiles. Furthermore, by verifying the OAM up-scaling law, we confirm OAM conservation during HHG in solids. These results establish strong-field HHG in solids as a robust platform for synthesizing ultrafast structured harmonic light with controllable, high-value OAM. + oai:arXiv.org:2512.19412v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Tobias R\"uttenauer, Kasimir Dederichs, David Kretschmer + Camilo Granados, B\'alint Kiss, Eric Cormier, Bikash Kumar Das, Debobrata Rajak, Carmelo Rosales-Guzman, Rajaram Shrestha, Qiwen Zhan, Wenlong Gao - Attosecond Control of Squeezed Light - https://arxiv.org/abs/2512.17046 - arXiv:2512.17046v1 Announce Type: cross -Abstract: Squeezed light has revolutionized quantum metrology by enhancing interferometry for sensitive applications such as the detection of gravitational waves. Squeezed light has also played a pivotal role in quantum information science with numerous applications in quantum computing and communication. Previously, squeezed light has been primarily generated using nonlinear optical interactions, where control of the degree of squeezing was possible by tuning the nonlinearity of the generating medium using suitable material engineering. Here, we modulate the third-order nonlinear response in dielectrics with strong ultrafast laser fields to control the degree of squeezing on attosecond time scales. We demonstrate the ability to change the ultrafast squeezed light generated in the nonlinear process from amplitude-squeezed to phase-squeezed by controlling the strong-field-driven nonlinear response of the material through a sub-cycle phase delay between the input femtosecond laser pulses. The squeezing of quantum noise is measured using a frequency-resolved balanced homodyne detection scheme capable of extracting the field quadratures in different frequency modes simultaneously. Using this frequency-resolved measurement we extract the complete coherency matrix containing the quantum correlations between field quadratures across different frequency modes of the femtosecond squeezed light pulse. These results have major implications for the development of quantum light sources with unprecedented levels of control over quadrature squeezing, for applications in multimode quantum information processing, and for measuring transient quantum matter correlations via transduction to quantum field correlations in an ultrafast light-matter interaction. - oai:arXiv.org:2512.17046v1 - quant-ph + Hair-thin confocal fluorescence endo-microscopy for deep-brain in-vivo imaging + https://arxiv.org/abs/2512.19419 + arXiv:2512.19419v1 Announce Type: new +Abstract: Confocal and multi-photon microscopy are widely used for in-vivo fluorescence imaging of biological tissues such as the brain, offering non-invasive access up to ~1 mm depth without major loss in performance. A recently-developed alternative is holographic endoscopy, which exploits controlled light transport through hair-thin optical fibres. With minimal invasiveness, it provides observations at comparable spatial resolution, while extending its applicability to unprecedented depths. It has been used to resolve details of sub-cellular structural connectivity, record neuronal signalling, and monitor blood flow from the deepest locations of the living brain. Yet, its use, particularly in densely labelled brain regions, has so far been constrained by significant contrast loss, primarily due to the absence of a practical mechanism for rejecting out-of-focus fluorescence light -- a capability inherently provided by confocal and multi-photon microscopy. Exploring opportunities in the structure of light modes of different MMF types we identify the possibility of achieving an analogue to confocal fluorescence microscopy through MMF-based endoscopes. Using a novel composite fibre probe that combines graded-index and step-index MMFs, we enable spatially resolved signal collection and selective rejection of out-of-focus light. This confocal filtering significantly enhances image contrast and resolution by suppressing background and off-plane signals. We demonstrate improved imaging performance on fine structural connectivity and intracellular calcium signalling in living mouse brain. + oai:arXiv.org:2512.19419v1 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 - cross + q-bio.NC + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Tom\'a\v{s} Pik\'alek, Miroslav Stib\r{u}rek, Tereza Tu\v{c}kov\'a, Petra Kolb\'abkov\'a, Sergey Turtaev, Jana Krej\v{c}\'i, Petra Ondr\'a\v{c}kov\'a, Hana Uhl\'i\v{r}ov\'a, Tom\'a\v{s} \v{C}i\v{z}m\'ar + + + Optimization of the characteristics of a relativistic electron beam based on laser wake-field acceleration using a non-symmetric gas target profile + https://arxiv.org/abs/2512.19431 + arXiv:2512.19431v1 Announce Type: new +Abstract: We demonstrate a high-energy, high-charge, electron source produced by the irradiation of a novel gaseous target by an ultra-intense femtosecond laser pulse. By exploiting a nonsymmetrical nozzle, we increased the total charge of the electron beam by at least an order of magnitude with respect to our previous experiments using symmetrical nozzles. In addition, the maximum energy of the accelerated electrons was enhanced by a factor of two. The electrons are accelerated via the Laser Wake-Field Acceleration mechanism. Particle-in-cell simulations indicate that electrons are injected via the ionization and the downramp injection mechanisms. Our measurements indicate that the demonstrated electron source is a considerable candidate for high dose, Very High Energy Electrons applications, such as radiotherapy. + oai:arXiv.org:2512.19431v1 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + D. Mancelli, G. Andrianaki, I. Tazes, C. Vlachos, I. Fitilis, I. Nikolos, M. Bakarezos, E. P. Benis, V. Dimitriou, N. A. Papadogiannis, M. Tatarakis + + + Ultra-high precision high voltage system for PTOLEMY + https://arxiv.org/abs/2512.19437 + arXiv:2512.19437v1 Announce Type: new +Abstract: The PTOLEMY project is prototyping a novel electromagnetic filter for high-precision $\beta$ spectroscopy, with the ultimate and ambitious long-term goal of detecting the cosmic neutrino background through electron capture on tritium bound to graphene. Intermediate small-scale prototypes can achieve competitive sensitivity to the effective neutrino mass, even with reduced energy resolution. To reach an energy resolution better than \SI{500}{meV} at the tritium $\beta$-spectrum endpoint of \SI{18.6}{keV}, and accounting for all uncertainties in the filtering chain, the electrode voltage must be controlled at the level of a few parts per million and monitored in real time. In this work, we present the first results obtained in this effort, using a chain of commercial ultra-high-precision voltage references, read out by precision multimeters and a \emph{field mill} device. The currently available precision on high voltage is, in the conservative case, as low as \SI{0.2}{ppm} per \SI{1}{kV} single board and $\lesssim$ \SI{50}{mV} over the \SI{10}{kV} series, presently limited by field mill read-out noise. However, assuming uncorrelated Gaussian noise extrapolation, the real precision could in principle be as low as \SI{0.05}{ppm} over \SI{20}{kV}. + oai:arXiv.org:2512.19437v1 + physics.ins-det + astro-ph.CO + hep-ex + Tue, 23 Dec 2025 00:00:00 -0500 + new http://creativecommons.org/licenses/by/4.0/ - Russell Zimmerman, Shashank Kumar, Shiva Kant Tiwari, Eric Liu, Francis Walz, Siddhant Pandey, George J. Economou II, Hadiseh Alaeian, Chen-Ting Liao, Valentin Walther, Niranjan Shivaram + R. Ammendola, A. Apponi, G. Benato, M. G. Betti, R. Biondim, P. Bos, G. Cavoto, M. Cadeddu, A. Casale, O. Castellano, E. Celasco, L. Cecchini, M. Chirico, W. Chung, A. G. Cocco, A. P. Colijn, B. Corcione, N. D'Ambrosio, M. D'Incecco, G. De Bellis, M. De Deo, N. de Groot, A. Esposito, M. Farino, S. Farinon, A. D. Ferella, L. Ferro, L. Ficcadenti, G. Galbato Muscio, S. Gariazzo, H. Garrone, F. Gatti, G. Korga, F. Malnati, G. Mangano, L. E. Marcucci, C. Mariani, J. Mead, G. Menichetti, M. Messina, E. Monticone, M. Naafs, V. Narcisi, S. Nagorny, G. Neri, F. Pandolfi, R. Pavarani, C. P\`erez de los Heros, O. Pisanti, C. Pepe, F. M. Pofi, A. D. Polosa, I. Rago, M. Rajteri N. Rossi, S. Ritarossi, A. Ruocco, G. Salina, A. Santucci, M. Sestu, A. Tan, V. Tozzini, C. G. Tully, I. van Rens, F. Virzi, G. Visser, M. Vivian - Selective trapping of bacteria in porous media by cell length - https://arxiv.org/abs/2512.17047 - arXiv:2512.17047v1 Announce Type: cross -Abstract: Bacteria commonly inhabit porous environments such as host tissues, soil, and marine sediments, where complex geometries constrain and redirect their motion. Although bacterial motility has been studied in porous media, the roles of cell length and pore shape in navigating these environments remain poorly understood. Here, we investigate how cell morphology and pore architecture jointly determine bacterial spreading behavior. Using genetically engineered E. coli with tunable cell length, we performed single-cell tracking in microfluidic devices that mimic ordered and disordered porous structures. We find that elongated bacteria traverse ordered pore networks more effectively than short cells, exhibiting straighter paths, greater directional persistence, and enhanced exploration efficiency. In contrast, in disordered porous media, elongated bacteria become trapped in dead-end regions for extended periods, resulting in markedly reduced navigational efficiency. Together, these results reveal how cell shape and environmental geometry interact to govern bacterial transport. Moreover, we suggest a new mechanism for separating antimicrobial-resistant (AMR) bacteria from elongated susceptible cells in designer porous media. - oai:arXiv.org:2512.17047v1 + Ferro-hydrodynamics of droplet necking filaments + https://arxiv.org/abs/2512.19459 + arXiv:2512.19459v1 Announce Type: new +Abstract: We explore the necking, filament thinning, and pinchoff dynamics of ferrofluid droplets within a magnetic field, via a simple and low-cost experimental method. In our studies, both the Ohnesorge number Oh and the Deborah number De are O1, a typically inaccessible regime with conventional extensional rheometers. Under magnetic forcing, the nanoparticles assemble into field aligned, chainlike structures, that generate a tunable magnetoelastic response, and markedly alter the extensional flow. Although behaving as Newtonian liquids in the absence of a magnetic field, the field induces extensional thickening, and the emergence of beads on a string BOAS structures in the ferrofluid filaments, a non-Newtonian signature. By combining controlled elongation with high speed imaging, we directly quantify the magnetic field-dependent extensional viscosity and relaxation time. Our findings underscore how magnetically induced microstructures govern filament stability and extensional dynamics in ferrofluids. + oai:arXiv.org:2512.19459v1 + physics.flu-dyn cond-mat.soft + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Neeladri Sekhar Bera, Apurba Roy, Purbarun Dhar + + + Gap-free Information Transfer in 4D-STEM via Fusion of Complementary Scattering Channels + https://arxiv.org/abs/2512.19460 + arXiv:2512.19460v1 Announce Type: new +Abstract: Linear phase-contrast scanning transmission electron microscopy (STEM) techniques compatible with high-throughput 4D-STEM acquisition are widely used to enhance phase contrast in weakly scattering and beam-sensitive materials. In these modalities, contrast transfer is often suppressed at low spatial frequencies, resulting in a characteristic contrast gap that limits quantitative imaging. Approaches that retain low-frequency phase contrast exist but typically require substantially increased experimental complexity, restricting routine use. Dark-field STEM imaging captures this missing low-frequency information through electrons scattered outside the bright-field disk, but discards a large fraction of the scattered signal and is therefore dose-inefficient. Fused Full-field STEM (FF-STEM) is introduced as a 4D-STEM imaging modality that overcomes this limitation by combining ptychographic phase reconstruction with tilt-corrected dark-field imaging within a single acquisition. Bright-field data are used to estimate probe aberrations and reconstruct a high-resolution phase image, while dark-field data provide complementary low-frequency contrast. The two channels are optimally fused in Fourier space using minimum-variance weighting based on the spectral signal-to-noise ratio, yielding transfer-gap-free images with high contrast and quantitative fidelity. FF-STEM preserves the upsampling and depth-sectioning capabilities of ptychography, adds robust low-frequency contrast characteristic of dark-field imaging, and enables dose-efficient, near-real-time reconstruction. + oai:arXiv.org:2512.19460v1 + physics.optics + cond-mat.mtrl-sci + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Shengbo You, Georgios Varnavides, Sagar Khavnekar, Nikita Palatkin, Sihan Shao, Mingjian Wu, Daniel Stroppa, Darya Chernikova, Baixu Zhu, Ricardo Egoavil, Stefano Vespucci, Xingchen Ye, Florian K. M. Schur, Erdmann Spiecker, Philipp Pelz + + + A Mathematical Framework for Misinformation Propagation in Complex Networks: Topology-Dependent Distortion and Control + https://arxiv.org/abs/2512.19465 + arXiv:2512.19465v1 Announce Type: new +Abstract: Misinformation is pervasive in natural, biological, social, and engineered systems, yet its quantitative characterization remains challenging.We develop a general mathematical framework for quantifying information distortion in distributed systems by modeling how local transmission errors accumulate along network geodesics and reshape each agent's perceived global state. Through a drift-fluctuation decomposition of pathwise binomial noise, we derive closed-form expressions for node-level perception distributions and show that directional bias induces only a uniform shift in the mean, preserving the fluctuation structure. Applying the framework to canonical graph ensembles, we uncover strong topological signatures of misinformation: Erd\H{o}s--R\'enyi random graphs exhibit a double-peaked distortion profile driven by connectivity transitions and geodesic-length fluctuations, scale-free networks suppress misinformation through hub-mediated integration, and optimally rewired small-world networks achieve comparable suppression by balancing clustering with short paths. A direct comparison across regular lattices, Erd\H{o}s--R\'enyi random graphs, Watts--Strogatz small-world networks, and Barab\'asi--Albert scale-free networks reveals a connectivity-dependent crossover. In the extremely sparse regime, scale-free and Erd\H{o}s--R\'enyi networks behave similarly. At intermediate sparsity, Watts--Strogatz small-world networks exhibit the lowest misinformation. In contrast, Barab\'asi--Albert scale-free networks maintain low misinformation in sparse and dense regimes, while regular lattices produce the highest distortion across connectivities. We additionally show how sparsity constraints, structural organization, and connection costs delineate regimes of minimal misinformation. + oai:arXiv.org:2512.19465v1 + physics.soc-ph + math.PR + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Saikat Sur, Rohitashwa Chattopadhyay, Jens Christian Claussen, Archan Mukhopadhyay + + + MRI Simulation and Reconstruction Framework for Magnetic Vector Fields + https://arxiv.org/abs/2512.19470 + arXiv:2512.19470v1 Announce Type: new +Abstract: Purpose: Conventional MRI is relying on the assumption of the magnetic field being homogeneous in direction and amplitude. However, with the growing interest in portable, affordable point-of-care MRI systems, these assumptions do not necessarily hold anymore due to compromises necessary to achieve a reduction in e.g. footprint, weight and portability. Simulation software may help by evaluating new encoding schemes which are optimized for non-ideal hardware but also with the design of new scanner designs. The goal of this work was to develop a MATLAB-based simulation software capable of dealing with deflected magnetic fields during signal simulation and reconstruction and enabling the evaluation of arbitrary magnetic field configurations for encoding in MRI. + Methods: Conventional matrix-based Bloch simulation is limited in its applicability to arbitrary magnetic fields. We therefore adapted, evaluated, and validated a modified approach, achieving substantially shorter simulation time. Furthermore, it is used to predict image quality in 2D gradient echo experiments with deflected magnetic fields. + Results: The comparison of numerical Bloch and matrix-based simulation revealed close agreement of both reconstructed images. Further, it was shown that compensation of the associated artifacts can be achieved by incorporating knowledge about the used magnetic fields into the reconstruction process. + Conclusion: The presented and validated software package enables full consideration of angular inhomogeneities of magnetic vector fields used in MRI for signal simulation but also reconstruction removing the related artifacts. As such, the software might become a valuable tool for new low-field system designs and the investigation of new reconstruction algorithms. + oai:arXiv.org:2512.19470v1 + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Fabian Bschorr, Thomas H\"ufken, Tobias Lobmeyer, Volker Rasche + + + Gold-polymer hybrid metasurface for polarization-independent enhanced third harmonic generation in the ultraviolet + https://arxiv.org/abs/2512.19483 + arXiv:2512.19483v1 Announce Type: new +Abstract: We present a combined experimental and theoretical study of nonlinear light-matter interactions in a three-dimensional gold-polymer hybrid metasurface. In contrast to conventional two-dimensional designs, which by symmetry may support either transverse electric (TE) or transverse magnetic (TM) polarization, our volumetric architecture accepts both TE and TM modes simultaneously, reflecting the dimensionality and versatility required by the photonic devices. The metasurface comprises a periodic lattice of gold nanostructures embedded in a dielectric polymer matrix, creating complex metal-dielectric interfaces that sustain tightly confined plasmonic resonances. When driven by ultrafast near-infrared pulses, these resonances concentrate optical energy at the nanoscale, enabling efficient third-harmonic generation and upconversion of visible light into the ultraviolet (UV) and deep-UV regimes with enhanced conversion efficiency. We perform spatial and temporal mapping of the nonlinear response under both TE and TM excitation. Our measurements reveal polarization-agnostic field enhancement and spectral tunability arising from the three-dimensional morphology-capabilities unattainable in planar metasurfaces, where two-dimensional symmetry inherently limits polarization flexibility and functional bandwidth. This 3D platform provides a flexible design toolbox for polarization-independent UV and deep-UV light sources. Potential applications include high-resolution UV spectroscopy, optical multiplexing, data storage, and emerging quantum photonic architectures. By establishing fundamental insights into three-dimensional nonlinear metasurface behavior, our work paves the way for next-generation reconfigurable, multi-polarization nanophotonic devices. + oai:arXiv.org:2512.19483v1 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Shroddha Mukhopadhyay, Ana Conde-Rubio, Jose Trull, Agustin Mihi, Michael Scalora, Maria Antonietta Vincenti, Crina Cojocaru + + + Time-domain anode-decoupling co-design for a floating MCP TOF-MS readout + https://arxiv.org/abs/2512.19495 + arXiv:2512.19495v1 Announce Type: new +Abstract: We present a microchannel plate detector for compact time-of-flight mass spectrometers (TOF-MS) that jointly optimizes the anode geometry and high-voltage AC-decoupling network for electrically floating operation. Undershoot-driven baseline artifacts and pulse broadening are addressed by a time-domain co-design of the anode geometry and decoupling network. The design is validated through a staged workflow that combines full-wave electromagnetic simulations, vector network analyzer measurements, circuit-level transient models, and end-to-end mass spectra. The resulting planar circular patch anode with anode-proximal decoupling confines fields, preserves peak amplitude, and suppresses post-pulse energy, leading to fast settling and minimal baseline wander. We show that the effective high-pass corner set by the decoupling capacitance directly governs undershoot decay and baseline recovery. Measurements in a representative TOF-MS test setup demonstrate waveguide-level pulse fidelity at a fraction of the mass and volume of heritage waveguide-based detectors, with residual ripples in the measured response originating from downstream cable and digitizer terminations rather than the detector itself. By limiting detector-induced temporal broadening and inter-peak baseline coupling, the design supports high mass resolution and dynamic range in miniaturized TOF-MS architectures. Variants of this planar flight-ready architecture are being implemented in several next-generation spaceborne TOF-MS instruments currently under development at the University of Bern. + oai:arXiv.org:2512.19495v1 + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Robin F. Bonny, Lorenzo Obersnel, Martin Rubin, Andr\'e Galli, Peter Wurz, Rico G. Fausch + + + A Collimation System Baseline Design for the Electron Storage Ring at the Electron-Ion Collider + https://arxiv.org/abs/2512.19502 + arXiv:2512.19502v1 Announce Type: new +Abstract: We present the baseline design of the electron ring collimation system for the Electron-Ion Collider (EIC) at Brookhaven National Laboratory (BNL). The system addresses beam losses in a high-current electron storage ring with superconducting (SC) final-focus magnets and sensitive detectors, where uncontrolled losses can generate heat loads, radiation, and detector backgrounds and damage. The proposed collimation insertion localizes halo particle losses through reducing interaction region beam losses from beam-gas and Touschek scattering by several orders of magnitude while keeping detector backgrounds and cryostat heat loads within acceptable limits. Multi-turn particle tracking simulations show that the collimators do not significantly impact machine acceptance or beam lifetime, and their positions and apertures can be re-optimized for future lattice configurations. Ongoing work includes incorporating crab cavities and solenoid fields into simulations, refining vacuum conditions, and optimizing collimator geometry and materials. This design establishes a robust baseline for the EIC electron ring collimation system and supports continued lattice optimization for machine operations. + oai:arXiv.org:2512.19502v1 + physics.acc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Andrii Natochii (Brookhaven National Laboratory, Upton, New York 11973, USA), Elke-Caroline Aschenauer (Brookhaven National Laboratory, Upton, New York 11973, USA), Karim Hamdi (Brookhaven National Laboratory, Upton, New York 11973, USA), Charles Hetzel (Brookhaven National Laboratory, Upton, New York 11973, USA), Eric Link (Brookhaven National Laboratory, Upton, New York 11973, USA), Daniel Marx (Brookhaven National Laboratory, Upton, New York 11973, USA), Christoph Montag (Brookhaven National Laboratory, Upton, New York 11973, USA), Steven Tepikian (Brookhaven National Laboratory, Upton, New York 11973, USA), Yunhai Cai (SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA), Yuri Nosochkov (SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA) + + + Energy dissipation mechanisms in an acoustically-driven slit + https://arxiv.org/abs/2512.19507 + arXiv:2512.19507v1 Announce Type: new +Abstract: We quantify how incident acoustic energy is converted into vortical motion and viscous dissipation for a two-dimensional plane-wave passing through a slit geometry. We perform direct numerical simulations over a broad parameter space in incident sound pressure level (ISPL), Strouhal number (St), and Reynolds number (Re). Spectral proper orthogonal decomposition (SPOD) yields energy-ranked coherent structures at each frequency, from which we construct mode-by-mode fields for spectral kinetic energy (KE) and viscous loss (VL) components to examine the mechanisms of acoustic absorption. At ISPL=150dB, the acoustic-hydrodynamic energy conversion is highest when the acoustic displacement amplitude is comparable to the slit thickness, corresponding to a Keulegan-Carpenter number of order unity. In this regime, the oscillatory boundary layer undergoes periodic separation, resulting in vortex shedding that dominates acoustic damping. VL accounts for 20-60% of the KE contribution. For higher acoustic frequencies, the confinement of the Stokes layer produces X-shaped near-slit modes, reducing the total energy input by approximately 50%. The influence of Re depends on amplitude. At ISPL=150dB, larger Re values correspond to suppressed broadband fluctuations and sharpened harmonic peaks. At ISPL = 120dB, the boundary layers remain attached, vortex shedding is weak, absorption monotonically scales with viscosity, and the Re- and St-dependencies become comparable. Across all conditions, more than 99% of the VL is confined to a compact region surrounding the slit mouth. The KE-VL spectra describe parameter regimes that enhance or suppress acoustic damping in slit geometries, providing a physically interpretable basis for acoustic-based design. + oai:arXiv.org:2512.19507v1 + physics.flu-dyn + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by/4.0/ + Haocheng Yu, Tianyi Chu, Spencer H. Bryngelson + + + Residential structure survivability to large wildfires in the United States + https://arxiv.org/abs/2512.19514 + arXiv:2512.19514v1 Announce Type: new +Abstract: Wildfire impacts on US communities have escalated in recent decades, highlighting the need to better understand factors that influence wildfire outcomes. We find that 567,000 homes were exposed to wildfires across the contiguous US during 2001-2020, two-thirds of which occurred and increased five-fold in the Western US. While residential structure survivability - the percent of structures within a wildfire perimeter that survive the fire - remained stable in the Eastern US in the past two decades, it declined by 10% in the West. Survivability was explained by structural age, surrounding fuels, and fire weather. Survivability was 87% for homes built pre-1990 compared to 92% for post-1990 homes in the West. Survivability was lowest in forests compared to grasslands and shrublands. Finally, survivability was markedly lower for fires coincident with extreme fire weather. Our results suggest that modern building codes, fuel management, and proactive planning can strengthen wildfire resilience. + oai:arXiv.org:2512.19514v1 + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Mukesh Kumar, John T. Abatzoglou, Crystal A. Kolden, Mojtaba Sadegh + + + Probability Conservation, Liouville Measure, and the Symplectic Origin of Hamiltonian Dynamics + https://arxiv.org/abs/2512.19533 + arXiv:2512.19533v1 Announce Type: new +Abstract: Liouville's theorem -- the preservation of phase-space volume -- is often presented as a corollary of Hamilton's canonical equations. Here we adopt an ensemble-first viewpoint in which the starting point is local probability conservation on phase space. For a probability density $\rho$ on a $2N$-dimensional symplectic manifold $(\mathcal{M},\omega)$, probability transport is expressed intrinsically with respect to the Liouville volume form $\Omega=\omega^N/N!$ through a continuity equation defined by the $\Omega$-divergence. For Hamiltonian evolution, specified by $\iota_{X_H}\omega=\mathrm{d}H$, Cartan's identity implies $\mathcal{L}_{X_H}\omega=0$ and hence $\mathcal{L}_{X_H}\Omega=0$, so the Hamiltonian flow is incompressible in the Liouville sense and the continuity law reduces to Liouville's equation. In canonical coordinates this reproduces Hamilton's equations. In particular, the canonical Poisson-bracket relations $\{q^i,p_j\}=\delta^i_{\ j}$ provide the kinematic input that fixes the evolution of observables and underlies the canonical form of the continuity equation. The same organization clarifies the distinction between conservation of total probability and preservation of fine-grained information measures (Gibbs--Shannon entropy), which holds specifically for Liouville-measure-preserving dynamics. + oai:arXiv.org:2512.19533v1 + physics.ed-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Enmanuel Rodr\'iguez-Brea, Melvin Arias + + + Active Convolved Illumination with Deep Transfer Learning for Complex Beam Transmission through Atmospheric Turbulence + https://arxiv.org/abs/2512.19540 + arXiv:2512.19540v1 Announce Type: new +Abstract: Atmospheric turbulence imposes a fundamental limitation across a broad range of applications, including optical imaging, remote sensing, and free-space optical communication. Recent advances in adaptive optics, wavefront shaping, and machine learning, driven by synergistic progress in fundamental theories, optoelectronic hardware, and computational algorithms, have demonstrated substantial potential in mitigating turbulence-induced distortions. Recently, active convolved illumination (ACI) was proposed as a versatile and physics-driven technique for transmitting structured light beams with minimal distortion through highly challenging turbulent regimes. While distinct in its formulation, ACI shares conceptual similarities with other physics-driven distortion correction approaches and stands to benefit from complementary integration with data-driven deep learning (DL) models. Inspired by recent work coupling deep learning with traditional turbulence mitigation strategies, the present work investigates the feasibility of integrating ACI with neural network-based methods. We outline a conceptual framework for coupling ACI with data-driven models and identify conditions under which learned representations can meaningfully support ACI's correlation-injection mechanism. As a representative example, we employ a convolutional neural network (CNN) together with a transfer-learning approach to examine how a learned model may operate in tandem with ACI. This exploratory study demonstrates feasible implementation pathways and establishes an early foundation for assessing the potential of future ACI-DL hybrid architectures, representing a step toward evaluating broader synergistic interactions between ACI and modern DL models. + oai:arXiv.org:2512.19540v1 + physics.optics + cs.LG + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Adrian A. Moazzam, Anindya Ghoshroy, Breeanne Heusdens, Durdu O. Guney, Roohollah Askari + + + Optimal Uncertainty Quantification under General Moment Constraints on Input Subdomains + https://arxiv.org/abs/2512.19572 + arXiv:2512.19572v1 Announce Type: new +Abstract: We present an optimal uncertainty quantification (OUQ) framework for systems whose uncertain inputs are characterized by truncated moment constraints defined over subdomains. Based on this partial information, rigorous optimal upper and lower bounds on the probability of failure (PoF) are derived over the admissible set of probability measures, providing a principled basis for system safety certification. We formulate the OUQ problem under general subdomain moment constraints and develop a high-performance computational framework to compute the optimal bounds. This approach transforms the original infinite-dimensional optimization problems into finite-dimensional unconstrained ones parameterized solely by free canonical moments. To address the prohibitive cost of PoF evaluation in high-dimensional settings, we incorporate inverse transform sampling (ITS), enabling efficient and accurate PoF estimation within the OUQ optimization. We also demonstrate that constraining inputs only by zeroth-order moments over subdomains yields a formulation equivalent to evidence theory. Three groups of numerical examples demonstrate the framework's effectiveness and scalability. Results show that increasing the number of subdomains or the moment order systematically tightens the bound interval. For high-dimensional problems, the ITS strategy reduces computational costs by up to two orders of magnitude while maintaining relative error below 1%. Furthermore, we identify regimes where optimal bounds are sensitive to subdomain partitioning or higher-order moments, guiding uncertainty reduction efforts for safety certification. + oai:arXiv.org:2512.19572v1 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Rong Jin, Xingsheng Sun + + + Transient Vibroacoustic Control of a Shock-Loaded Inter-Connected Cylindrical Double Shell + https://arxiv.org/abs/2512.19573 + arXiv:2512.19573v1 Announce Type: new +Abstract: Double-wall cylindrical shells are widely used in applications where resistance to acoustic shock loading is critical. While the transient vibroacoustic behavior of single-walled shells has been extensively investigated, extending these analyses to double-wall cylindrical configurations introduces increased complexity due to multiple inter-shell acoustic reflections and strong coupling between acoustic fields and structural vibrations. These structures often feature mechanical interconnections between the shells to ensure structural integrity, load sharing, alignment, and enhanced resilience against static and dynamic loads. These links introduce additional pathways for vibration transmission and significantly influence the overall behavior of the system, thus making the analytical description of the coupled vibroacoustic response even more challenging. This study investigates the transient vibroacoustics of an inter-connected double-wall cylindrical shell subjected to an acoustic shock, considering fully coupled fluid-structure interactions. A comprehensive two-dimensional acoustoelastic model is developed in polar coordinates, incorporating the surrounding medium, the fluid occupying the inter-shell gap, and the fluid inside the inner shell. A semi-analytical solution method is employed to capture the time-domain evolution of acoustic fields and shell vibrations. The model's accuracy is verified by benchmarking against available data reported in the literature. Leveraging the passive dynamics of the system, we present a hybrid mechanism that integrates optimized nonlinear vibration absorbers with piezoelectric actuators to control the vibroacoustic behavior. The results demonstrate the effectiveness of the proposed hybrid mechanism in mitigating shock-induced acoustic pressure waves and enhancing the structural resilience of the double-wall cylindrical shell. + oai:arXiv.org:2512.19573v1 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Rahim Vesal, Seyyed Mohammad Hasheminejad, Herv\'e Lissek + + + Picosecond laser test unit for photosensor characterization at ambient and low temperatures + https://arxiv.org/abs/2512.19667 + arXiv:2512.19667v1 Announce Type: new +Abstract: Accurate single photoelectron (SPE) characterization of photosensors is essential for controlling systematic uncertainties in low-light neutrino and dark matter detectors. We present a compact laboratory setup for the characterization of photosensors under controlled, low-light conditions. Specifically, we demonstrate its use with photomultiplier tubes (PMTs) operated at the SPE-level, using picosecond laser pulses and waveform digitization to determine key PMT properties. Measurements as a function of supply voltage and temperature ($-50^\circ$C to $+20^\circ$C) are performed on ET Enterprises 9821(Q)B tubes and a Hamamatsu R9980 assembly, which show exponential gain-voltage behavior and device-to-device variation. Cooling increases the gain by $\sim 0.1\,\%/^\circ$C, while the transit time spread (TTS) and peak-to-valley ratio (P/V) exhibit no clear temperature dependence. TTS decreases with voltage. Late pulses remain at the percent level and prepulses at the sub-percent level. Cable length affects both apparent gain and TTS. A model-independent, data-driven self-convolution method is introduced to quantify double photoelectron contributions from pulse charge spectra. The procedures provide a reproducible, practice-oriented reference for SPE-level PMT characterization and can be extended to other photosensor types. + oai:arXiv.org:2512.19667v1 + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 + new + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Matthias Raphael Stock (Technical University of Munich, TUM School of Natural Sciences, Department of Physics), Hans Th. J. Steiger (Technical University of Munich, TUM School of Natural Sciences, Department of Physics, Johannes Gutenberg University Mainz, Institute of Physics), Ulrike Fahrendholz (Technical University of Munich, TUM School of Natural Sciences, Department of Physics), Luca Schweizer (Technical University of Munich, TUM School of Natural Sciences, Department of Physics), Lothar Oberauer (Technical University of Munich, TUM School of Natural Sciences, Department of Physics) + + + Physics-Informed Lightweight Machine Learning for Aviation Visibility Nowcasting Across Multiple Climatic Regimes + https://arxiv.org/abs/2512.16967 + arXiv:2512.16967v1 Announce Type: cross +Abstract: Short-term prediction (nowcasting) of low-visibility and precipitation events is critical for aviation safety and operational efficiency. Current operational approaches rely on computationally intensive numerical weather prediction guidance and human-issued TAF products, which often exhibit conservative biases and limited temporal resolution. This study presents a lightweight gradient boosting framework (XGBoost) trained exclusively on surface observation data (METAR) and enhanced through physics-guided feature engineering based on thermodynamic principles. The framework is evaluated across 11 international airports representing distinct climatic regimes (including SCEL, KJFK, KORD, KDEN, SBGR, and VIDP) using historical data from 2000 to 2024. Results suggest that the model successfully captures underlying local physical processes without manual configuration. In a blind comparative evaluation against operational TAF forecasts, the automated model achieved substantially higher detection rates at tactical horizons (3 hours), with a 2.5 to 4.0 times improvement in recall while reducing false alarms. Furthermore, SHAP analysis reveals that the model performs an implicit reconstruction of local physical drivers (advection, radiation, and subsidence), providing actionable explainability for operational situational awareness. + Keywords: aviation meteorology; physics-guided machine learning; explainable artificial intelligence; lightweight machine learning; nowcasting; METAR; TAF verification; edge computing + oai:arXiv.org:2512.16967v1 + cs.LG + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Marcelo Cerda Castillo + + + A proof-of-principle experiment on the spontaneous symmetry breaking machine and numerical estimation of its performance on the $K_{2000}$ benchmark problem + https://arxiv.org/abs/2512.17922 + arXiv:2512.17922v1 Announce Type: cross +Abstract: In a previous paper, we proposed a unique physically implemented type simulator for combinatorial optimization problems, called the spontaneous symmetry breaking machine (SSBM). In this paper, we first report the results of experimental verification of SSBM using a small-scale benchmark system, and then describe numerical simulations using the benchmark problems (K2000) conducted to confirm its usefulness for large-scale problems. From 1000 samples with different initial fluctuations, it became clear that SSBM can explore a single extremely stable state. This is based on the principle of a phenomenon used in SSBM, and could be a notable advantage over other simulators. + oai:arXiv.org:2512.17922v1 + math.OC + nlin.AO + physics.optics + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Toshiya Sato, Takashi Goh + + + Stylized Facts and Their Microscopic Origins: Clustering, Persistence, and Stability in a 2D Ising Framework + https://arxiv.org/abs/2512.17925 + arXiv:2512.17925v1 Announce Type: cross +Abstract: The analysis of financial markets using models inspired by statistical physics offers a fruitful approach to understand collective and extreme phenomena [3, 14, 15] In this paper, we present a study based on a 2D Ising network model where each spin represents an agent that interacts only with its immediate neighbors plus a term reated to the mean field [1, 2]. From this simple formulation, we analyze the formation of spin clusters, their temporal persistence, and the morphological evolution of the system as a function of temperature [5, 19]. Furthermore, we introduce the study of the quantity $1/2P\sum_{i}|S_{i}(t)+S_{i}(t+\Delta t)|$, which measures the absolute overlap between consecutive configurations and quantifies the degree of instantaneous correlation between system states. The results show that both the morphology and persistence of the clusters and the dynamics of the absolute sum can explain universal statistical properties observed in financial markets, known as stylized facts [2, 12, 18]: sharp peaks in returns, distributions with heavy tails, and zero autocorrelation. The critical structure of clusters and their reorganization over time thus provide a microscopic mechanism that gives rise to the intermittency and clustered volatility observed in prices [2, 15]. + oai:arXiv.org:2512.17925v1 + q-fin.ST + nlin.AO + physics.soc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Physica A (2025) + Hern\'an Ezequiel Ben\'itez, Claudio Oscar Dorso + + + Investigating Hamiltonian Dynamics by the Method of Covariant Lyapunov Vectors + https://arxiv.org/abs/2512.17962 + arXiv:2512.17962v1 Announce Type: cross +Abstract: In this thesis, we review the theory of Lyapunov exponents and covariant Lyapunov vectors (CLVs) and use these objects to numerically investigate the dynamics of several autonomous Hamiltonian systems. The algorithm which we use for computing CLVs is the one developed by Ginelli and collaborators (G&C), which is quite efficient and has been used previously in many numerical investigations. Using two low-dimensional Hamiltonian systems as toy models, we develop a method for measuring the convergence rates of vectors and subspaces computed via the G&C algorithm, and we use the time it takes for this convergence to occur to determine the appropriate transient time lengths needed when applying this algorithm to compute CLVs. The tangent dynamics of the centre subspace of the H\'enon-Heiles system is investigated numerically through the use of CLVs, and we propose a method that improves the accuracy of the centre subspace computed with the G&C algorithm. As another application of the method of CLVs to the H\'enon-Heiles system, we find that the splitting subspaces (which form a splitting of the tangent space and define the CLVs) become almost tangent during sticky regimes of motion, an observation which is related to the hyperbolicity of the system. Additionally, we investigate the dynamics of bubbles (i.e. thermal openings between base pairs) in homogeneous DNA sequences using the Peyrard-Bishop-Dauxois lattice model of DNA. For the purpose of studying short-lived bubbles in DNA, the notions of instantaneous Lyapunov vectors (ILVs) are introduced in the context of Hamiltonian dynamics. While we find that the size of the opening between base pairs has no clear relationship with the spatial distribution of the first CLV at that site, we do observe a distinct relationship with various ILV distributions. + oai:arXiv.org:2512.17962v1 + nlin.CD + math.DS + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jean-Jacq du Plessis + + + Systematizing the Interpretation of Quantum Theory via Reconstruction + https://arxiv.org/abs/2512.18002 + arXiv:2512.18002v1 Announce Type: cross +Abstract: For a century, quantum theory has posed a fundamental challenge to philosophical thinking. On its face, it repudiates many of the key features of the mechanical conception of physical reality. However, the challenge of developing a precise, coherent alternative to that conception has yet to be met. Here, I argue that a major hindrance to the project of quantum interpretation is its existing interpretative methodologies, which suffer from a lack of systematicity in their judgements about what aspects of the theory are interpretational relevant. In particular, I argue that current interpretations tend to marginalize the informal part of the theory in favour of its formal part, and place inappropriate emphasis on the natural language component of the formalism over its detailed mathematical structure. To counterbalance these biases, I propose that an interpretation-free zone be constructed around the theory, wherein an interpreter initially adopt a descriptive stance which considers all parts of the theory, and that the results of this deliberation~(and the judgements about what facts are interpretationally relevant) are reported as part of their interpretation. + I argue that the interpretation of quantum theory poses special challenges and difficulties which necessitate this interpretation-free zone, and that existing interpretative methodologies are insufficient to address them. Further, I argue that a reconstructive interpretative methodology, which harnesses the recent results of the quantum reconstruction program, provides a powerful means to identify almost all facts that could be interpretationally relevant, and naturally meets these challenges and difficulties. Moreover, I argue that the quantum reconstruction program offers a powerful way to discover new physical principles, and offers a systematic pathway to build a rich, coherent conception of quantum reality. + oai:arXiv.org:2512.18002v1 + quant-ph + physics.hist-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Philip Goyal + + + Monitoring and Evaluating Astronomy-for-Development Initiatives + https://arxiv.org/abs/2512.18015 + arXiv:2512.18015v1 Announce Type: cross +Abstract: This paper serves as a practical guide for individuals and organisations seeking to design, implement, and evaluate astronomy-for-development initiatives, as well as those preparing proposals for the International Astronomical Union's Office of Astronomy for Development (IAU OAD) annual Call for Proposals. The paper aims to outline how systematic evidence collection can strengthen project design, enhance accountability, and increase the likelihood of measurable impact. It explains the distinction between monitoring and evaluation, provides guidance on when and how evaluation should be undertaken, and summarises key evaluation types - process, feasibility, impact, outcome, economic, and summative, relevant to astronomy-based interventions. In addition to conceptual discussion, the paper presents a set of practical steps, reflective questions, and examples to help project teams develop a clear theory of change, define appropriate indicators, and anticipate risks and unintended consequences. By contextualising M&E within the broader goals of the OAD and the Sustainable Development Goals (SDGs), this work aims to empower practitioners to create evidence-informed, community-driven, and sustainable astronomy-for-development projects that deliver both local and global benefit. + oai:arXiv.org:2512.18015v1 + astro-ph.IM + physics.soc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Joyful E. Mdhluli (on behalf of the IAU Office of Astronomy for Development) + + + Optimization of Si/SiGe Heterostructures for Large and Robust Valley Splitting in Silicon Qubits + https://arxiv.org/abs/2512.18064 + arXiv:2512.18064v1 Announce Type: cross +Abstract: The notoriously low and fluctuating valley splitting is one of the key challenges for electron spin qubits in silicon (Si), limiting the scalability of Si-based quantum processors. In silicon-germanium (SiGe) heterostructures, the problem can be addressed by the design of the epitaxial layer stack. Several heuristic strategies have been proposed to enhance the energy gap between the two nearly degenerate valley states in strained Si/SiGe quantum wells (QWs), e.g., sharp Si/SiGe interfaces, Ge spikes or oscillating Ge concentrations within the QW. In this work, we develop a systematic variational optimization approach to compute optimal Ge concentration profiles that boost selected properties of the intervalley coupling matrix element. Our free-shape optimization approach is augmented by a number of technological constraints to ensure feasibility of the resulting epitaxial profiles. The method is based on an effective-mass-type envelope-function theory accounting for the effects of strain and compositional alloy disorder. Various previously proposed heterostructure designs are recovered as special cases of the constrained optimization problem. Our main result is a novel heterostructure design we refer to as the "modulated wiggle well," which provides a large deterministic enhancement of the valley splitting along with a reliable suppression of the disorder-induced volatility. In addition, our new design offers a wide-range tunability of the valley splitting ranging from about 200 $\mu$eV to above 1 meV controlled by the vertical electric field, which offers new perspectives to engineer switchable qubits with on-demand adjustable valley splitting. + oai:arXiv.org:2512.18064v1 + cond-mat.mes-hall + math.OC + physics.app-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Abel Thayil, Lasse Ermoneit, Lars R. Schreiber, Thomas Koprucki, Markus Kantner + + + The CHSH Game, Tsirelson's Bound, and Causal Locality + https://arxiv.org/abs/2512.18105 + arXiv:2512.18105v1 Announce Type: cross +Abstract: We reformulate the CHSH game in terms of indivisible stochastic processes. Using Barandes's stochastic-quantum correspondence and its associated definition of causal locality, we present a novel proof of the Tsirelson bound. In particular, we show that unlike the no-signaling principle alone, the postulates defining causally local, indivisible stochastic processes are precisely strong enough to allow for violations of the Bell inequality up to, but not beyond, the Tsirelson bound. + oai:arXiv.org:2512.18105v1 + quant-ph + physics.hist-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Jacob A. Barandes, Mahmudul Hasan, David Kagan + + + Optimizing Epsilon Security Parameters in QKD + https://arxiv.org/abs/2512.18130 + arXiv:2512.18130v1 Announce Type: cross +Abstract: We investigate the optimization of epsilon-security parameters in quantum key distribution (QKD), aiming to improve the achievable secure key rate under a fixed overall composable security level. For this purpose, we employ a continuous genetic algorithm (CGA) to optimize the epsilon-security components of two representative protocols: the homodyne protocol from the continuous-variable (CV) family and the BB84 protocol from the discrete-variable (DV) family. We detail the CGA configuration, summarize the derivation of the composable key rate, and emphasize the role of the epsilon-parameters in both protocols. We then compare key rates obtained with optimized epsilon-values against those derived from standard and randomized choices. Our results demonstrate substantial key rate improvements at high security levels, where the key rate typically vanishes, and uncover positive-rate regimes that are inaccessible without optimization. + oai:arXiv.org:2512.18130v1 + quant-ph + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Alexander G. Mountogiannakis, Stefano Pirandola + + + A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array + https://arxiv.org/abs/2512.18142 + arXiv:2512.18142v1 Announce Type: cross +Abstract: In 2025 July, the third-ever interstellar object, 3I/ATLAS, was discovered on its ingress into the Solar System. Similar to the NASA Voyager missions sent in 1977, science probes by extraterrestrial life (artifact ``technosignatures'') could be sent to explore other stellar systems like our own. In this campaign, we used the SETI Institute's Allen Telescope Array to observe 3I/ATLAS from 1--9~GHz. We detected nearly 74 million narrowband hits in 7.25~hr of data using the newly-developed search pipeline \texttt{bliss}. We then applied blanking in frequency and drift rate to mitigate Radio Frequency Interference (RFI) in our dataset, narrowing the dataset down to $\sim$2 million hits. These hits were further filtered by the localization code \texttt{NBeamAnalysis}, and the remaining 211 hits were visually inspected in the time-frequency domain. We did not find any signals worthy of additional follow-up. Accounting for the Doppler drift correction and given the non-detection, we are able to set an Effective Isotropic Radiated Power (EIRP) upper limit of $10-110$~W on radio technosignatures from 3I/ATLAS across the frequency and drift rate ranges covered by our survey. + oai:arXiv.org:2512.18142v1 + astro-ph.EP + astro-ph.IM + physics.pop-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Sofia Z. Sheikh, Valeria Garcia Lopez, Isabel Gerrard, James R. A. Davenport, Wael Farah, Blayne Griffin, Steve Croft, Luigi F. Cruz, Imke de Pater, Ben Jacobson-Bell, Mark Masters, Karen I. Perez, Alexander W. Pollak, Carol Shumaker, Andrew Siemion + + + Estimating Solvation Free Energies with Boltzmann Generators + https://arxiv.org/abs/2512.18147 + arXiv:2512.18147v1 Announce Type: cross +Abstract: Accurate calculations of solvation free energies remain a central challenge in molecular simulations, often requiring extensive sampling and numerous alchemical intermediates to ensure sufficient overlap between phase-space distributions of a solute in the gas phase and in solution. Here, we introduce a computational framework based on normalizing flows that directly maps solvent configurations between solutes of different sizes, and compare the accuracy and efficiency to conventional free energy estimates. For a Lennard-Jones solvent, we demonstrate that this approach yields acceptable accuracy in estimating free energy differences for challenging transformations, such as solute growth or increased solute-solute separation, which typically demand multiple intermediate simulation steps along the transformation. Analysis of radial distribution functions indicates that the flow generates physically meaningful solvent rearrangements, substantially enhancing configurational overlap between states in configuration space. These results suggest flow-based models as a promising alternative to traditional free energy estimation methods. + oai:arXiv.org:2512.18147v1 + cond-mat.stat-mech + cs.LG + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Maximilian Schebek, Nikolas M. Frob\"ose, Bettina G. Keller, Jutta Rogal + + + Symmetry breaking transforms strong to normal correlation and false metals to true insulators + https://arxiv.org/abs/2512.18236 + arXiv:2512.18236v1 Announce Type: cross +Abstract: Material scientists and condensed matter physicists have long been divided on the issue of choosing the conceptual framework for explaining why open-shell transition-metal oxides tend to be insulators, whereas otherwise successful theories such as DFT often predict them to be (false) metals. Strong correlation becomes the recommended medicine. We point out that strong correlation can be mitigated by allowing DFT to lower the energy by breaking structural, magnetic or dipolar symmetries. Such local motifs are observed experimentally by local probes beyond the 'average structure' determined by X-Ray diffraction. Observed broken symmetries can arise from slow fluctuations that persist over the observation time or longer. The surprising fact is that when symmetry breaking motifs are used as input to electronic structure calculations, false metals are converted into real insulators without the recommended medicine of strong correlation. Consistently, DFT calculations that show energy lowering symmetry breaking correct most cases where DFT, even with advanced exchange-correlation functionals, previously missed the correct metal vs insulator designation. Total energy calculations distinguish systems that support energy-lowering symmetry breaking from those that do not. This approach distinguishes between paramagnetic insulating and metallic phases and shows mass enhancement in Mott metals. The reason is that symmetry breaking removes many of the degeneracies that exist in a symmetry-unbroken system, reducing significantly the need for strong correlation. If one chooses to ignore symmetry breaking, the persistent degeneracies often call for strong correlation treatment. Thus, symmetry breaking transforms strong to normal correlation and false metals to true insulators. This view sheds light on the historic controversy between Mott and Slater that still reverberates today. + oai:arXiv.org:2512.18236v1 + cond-mat.mtrl-sci + cond-mat.str-el + physics.comp-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Alex Zunger, Jia-Xin Xiong, John P. Perdew + + + CrystalFormer-CSP: Thinking Fast and Slow for Crystal Structure Prediction + https://arxiv.org/abs/2512.18251 + arXiv:2512.18251v1 Announce Type: cross +Abstract: Crystal structure prediction is a fundamental problem in materials science. We present CrystalFormer-CSP, an efficient framework that unifies data-driven heuristic and physics-driven optimization approaches to predict stable crystal structures for given chemical compositions. The approach combines pretrained generative models for space-group-informed structure generation and a universal machine learning force field for energy minimization. Reinforcement fine-tuning can be employed to further boost the accuracy of the framework. We demonstrate the effectiveness of CrystalFormer-CSP on benchmark problems and showcase its usage via web interface and language model integration. + oai:arXiv.org:2512.18251v1 + cond-mat.mtrl-sci + cs.LG + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Zhendong Cao, Shigang Ou, Lei Wang + + + Multi-Functional Properties of Manganese Pnictides: A First-Principles Study on Magneto-Optics and Magnetocaloric Properties + https://arxiv.org/abs/2512.18253 + arXiv:2512.18253v1 Announce Type: cross +Abstract: Magnetic refrigeration presents an energy-efficient and environmentally benign alternative to traditional vapour-compression cooling technologies. It relies on the magnetocaloric effect, in which the temperature of a magnetic material changes in response to variations in an applied magnetic field. Optimal magnetocaloric materials are characterized by a significant change in magnetic entropy under moderate magnetic field. In this study, we systematically investigated the inter-atomic exchange interactions, magnetic anisotropy energy and magnetocaloric properties of MnX (X = N, P, As, Sb, Bi) using a combination of density functional theory and Monte-Carlo simulations. Additionally, the magneto-optical Kerr and Faraday spectra were computed using the all-electron, fully relativistic, full-potential linearized muffin-tin orbital method. The largest Kerr effect observed in MnBi can be inferred as a combined effect of maximal exchange splitting of Mn 3d states and the large spin-orbit coupling of Bi. To extract site-projected spin and orbital moments, spin-orbit coupling and orbital polarization correction are accounted in the present calculation, which shows good agreement between the moment obtained from the X-ray magnetic circular dichroism sum rule analysis, spin-polarized calculation, and experimental studies. The magnetic transition temperatures predicted through Monte-Carlo simulations were in good agreement with the corresponding experimental values. Our results provide a unified microscopic understanding of magnetocaloric performance and magneto-optical activity in Mn-based pnictides and establish a reliable computational framework for designing next-generation magnetic refrigeration materials. + oai:arXiv.org:2512.18253v1 + cond-mat.mtrl-sci + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Jayendran S, Abhishek K G, Suresh R, Helmer Fjellv{\aa}g, Ravindran P + + + Robust and scalable simulation-based inference for gravitational wave signals with gaps + https://arxiv.org/abs/2512.18290 + arXiv:2512.18290v1 Announce Type: cross +Abstract: The Laser Interferometer Space Antenna (LISA) data stream will inevitably contain gaps due to maintenance and environmental disturbances, introducing nonstationarities and spectral leakage that compromise standard frequency-domain likelihood evaluations. We present a scalable Simulation-Based Inference (SBI) framework capable of robust parameter estimation directly from gapped time-series data. We employ Flow Matching Posterior Estimation (FMPE) conditioned on a learned summary of the data, optimized through an end-to-end training strategy. To address the computational challenges of long-duration signals, we propose a dual-pathway summarizer architecture: a 1D Convolutional Neural Network (CNN) operating on the time domain for high precision, and a novel wavelet-based 2D CNN utilizing asymmetric, dilated kernels to achieve scalability for datasets spanning months. We demonstrate the efficacy of this framework on simulated Galactic Binary-like signals, showing that our joint training approach yields tighter, unbiased posteriors compared to two-stage reconstruction pipelines. Furthermore, we provide the first systematic comparison showing that FMPE offers superior stability and coverage calibration over conventional Normalizing Flows in the presence of severe data artifacts. + oai:arXiv.org:2512.18290v1 + astro-ph.IM + gr-qc + physics.data-an + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Ruiting Mao, Jeong Eun Lee, Matthew C. Edwards + + + Nonlocal and nonlinear plasmonics in atomically thin heterostructures + https://arxiv.org/abs/2512.18339 + arXiv:2512.18339v1 Announce Type: cross +Abstract: Plasmons in atomically thin materials offer a compelling route to trigger nonlinear light-matter interactions through extreme optical confinement in the two-dimensional (2D) limit. However, optical nonlocality in plasmons is typically associated with losses in the linear response regime. Here, we show that nonlocal effects mediate strong plasmon-assisted optical nonlinearity in electrically reconfigurable 2D heterostructures. Using atomistic simulations that capture quantum finite-size and nonlocal effects in the nonlinear plasmonic response of graphene and phosphorene nanoribbon dimers, we reveal how symmetry and inter-ribbon coupling shape harmonic generation processes in perturbative and high-harmonic regimes. Independent tuning of geometry and carrier density in nanoribbon heterostructures is shown to induce inter-ribbon plasmon hybridization, impacting inversion symmetry governing even-ordered nonlinear processes like second-harmonic generation. These results reveal design principles for active and passive tuning of nonlinear plasmonic effects and enable selective enhancement of specific harmonic processes, establishing 2D heterostructures as a versatile platform for nonlinear nanophotonics. + oai:arXiv.org:2512.18339v1 + cond-mat.mes-hall + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Line Jelver, Joel D. Cox + + + Multiresolution analysis of quantum theories using Daubechies wavelet basis + https://arxiv.org/abs/2512.18372 + arXiv:2512.18372v1 Announce Type: cross +Abstract: Flow equation methods, more generally known as Similarity Renormalization Group (SRG) techniques, were developed to address multiscale problems where multiple length or energy scales contribute simultaneously. In this Thesis, we formulate the flow equation method within a wavelet-based framework and apply it to study scale (resolution) separation in a two-dimensional scalar field theory. We demonstrate that the flow systematically block-diagonalizes the Hamiltonian with respect to wavelet resolution, achieving improved truncation compared to earlier studies. Using a model of two real scalar fields coupled through a quadratic interaction, we show that the flow equations effectively suppress couplings between low- and high-resolution degrees of freedom. This provides a clear mechanism for isolating low-resolution physics and offers insight into the construction of effective Hamiltonians using a wavelet-based flow equation approac + oai:arXiv.org:2512.18372v1 + hep-th + hep-lat + hep-ph + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/publicdomain/zero/1.0/ + Mrinmoy Basak + + + Size-Consistent Quantum Chemistry on Quantum Computers + https://arxiv.org/abs/2512.18395 + arXiv:2512.18395v1 Announce Type: cross +Abstract: Hybrid quantum-classical algorithms have begun to leverage quantum devices to efficiently represent many-electron wavefunctions, enabling early demonstrations of molecular simulations on real hardware. A key prerequisite for scalable quantum chemistry, however, is size consistency: the energy of non-interacting subsystems must scale linearly with system size. While many algorithms are theoretically size-consistent, noise on quantum devices may couple nominally independent subsystems and degrade this fundamental property. Here, we systematically evaluate size consistency on quantum hardware by simulating systems composed of increasing numbers of non-interacting H$_{2}$ molecules using optimally shallow unitary circuits. We find that molecular energies remain size-consistent within chemical accuracy for an estimated 118 and 71 H$_{2}$ subsystems for one- and two-qubit unitary designs, respectively, demonstrating that current quantum devices preserve size consistency over chemically relevant system sizes and supporting the feasibility of scalable, noise-resilient simulation of strongly correlated molecules and materials. + oai:arXiv.org:2512.18395v1 + quant-ph + physics.chem-ph + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Noah Garrett, Michael Rose, David A. Mazziotti + + + Momentum-resolved spectral functions of super-moir\'e systems using tensor networks + https://arxiv.org/abs/2512.18397 + arXiv:2512.18397v1 Announce Type: cross +Abstract: Computing spectral functions in large, non-periodic super-moir\'e systems remains an open problem due to the exceptionally large system size that must be considered. Here, we establish a tensor network methodology that allows computing momentum-resolved spectral functions of non-interacting and interacting super-moir\'e systems at an atomistic level. Our methodology relies on encoding an exponentially large tight-binding problem as an auxiliary quantum many-body problem, solved with a many-body kernel polynomial tensor network algorithm combined with a quantum Fourier transform tensor network. We demonstrate the method for one and two-dimensional super-moir\'e systems, including super-moir\'e with non-uniform strain, interactions treated at the mean-field level, and quasicrystalline super-moir\'e patterns. Furthermore, we demonstrate that our methodology allows us to compute momentum-resolved spectral functions restricted to selected regions of a super-moir\'e, enabling direct imaging of position-dependent electronic structure and minigaps in super-moir\'e systems with non-uniform strain. Our results establish a powerful methodology to compute momentum-resolved spectral functions in exceptionally large super-moir\'e systems, providing a tool to directly model scanning twisting microscope tunneling experiments in twisted van der Waals heterostructures. + oai:arXiv.org:2512.18397v1 + cond-mat.str-el + cond-mat.mes-hall + cond-mat.mtrl-sci + physics.comp-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Anouar Moustaj, Yitao Sun, Tiago V. C. Antao, Jose L. Lado + + + A least-squares meshfree method for the incompressible Navier-Stokes equations: A satisfactory solenoidal velocity field via a staggered-variable arrangement + https://arxiv.org/abs/2512.18422 + arXiv:2512.18422v1 Announce Type: cross +Abstract: Incompressible flow solvers based on strong-form meshfree methods represent arbitrary geometries without the need for a global mesh system. However, their local evaluations make it difficult to satisfy incompressibility at the discrete level. Moreover, the collocated arrangement of velocity and pressure variables tends to induce a zero-energy mode, leading to decoupling between the two variables. In projection-based approaches, a spatial discretization scheme based on a conventional node-based moving least-squares method for the pressure causes inconsistency between the discrete operators on both sides of the Poisson equation. Thus, a solenoidal velocity field cannot be ensured numerically. In this study, a numerical method for the incompressible Navier-Stokes equations is developed by introducing a local primal-dual grid into the mesh-constrained discrete point method, enabling consistent discrete operators. The \textit{virtual} dual cell constructed is based on the local connectivity among nodes, and therefore our method remains truly meshfree. To achieve a consistent coupling between velocity and pressure variables under the primal-dual arrangement, time evolution converting is applied to evolve the velocity on cell interfaces. For numerical validation, a linear acoustic equation is solved to confirm the effectiveness of the staggered-variable arrangement based on the local primal-dual grid. Then, incompressible Navier-Stokes equations are solved, and the proposed method is demonstrated to satisfy the condition of a solenoidal velocity field at the discrete level, achieve the expected spatial convergence order, and accurately reproduce flow features over a wide range of Reynolds numbers. + oai:arXiv.org:2512.18422v1 + math.NA + cs.NA + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Takeharu Matsuda, Satoshi Ii + + + Global Regular Solutions of the Multidimensional Degenerate Compressible Navier-Stokes Equations with Large Initial Data of Spherical Symmetry + https://arxiv.org/abs/2512.18545 + arXiv:2512.18545v1 Announce Type: cross +Abstract: A fundamental open problem in the theory of the compressible Navier-Stokes equations is whether regular spherically symmetric flows can develop singularities -- such as cavitation or implosion -- in finite time. A formidable challenge lies in how the well-known coordinate singularity at the origin can be overcome to control the lower or upper bound of the density. For the barotropic Navier-Stokes system with constant viscosity coefficients, recent striking results have shown that such implosions do indeed occur. In this paper, we show that the situation is fundamentally different when the viscosity coefficients are degenerately density-dependent (as in the shallow water equations). We prove that, for general large spherically symmetric initial data with bounded positive density, solutions remain globally regular and cannot undergo cavitation or implosion in two and three spatial dimensions. Our results hold for all adiabatic exponents $\gamma\in (1,\infty)$ in two dimensions, and for physical adiabatic exponents $\gamma\in (1, 3)$ in three dimensions, without any restriction on the size of the initial data. To achieve these results, we make carefully designed weighted radial estimates via a region segmentation method, which is the key for obtaining uniform control over both the density and the effective velocity. The methodology developed here should also be useful for solving other related nonlinear partial differential equations involving similar difficulties. + oai:arXiv.org:2512.18545v1 + math.AP + math-ph + math.MP + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Gui-Qiang G. Chen, Jiawen Zhang, Shengguo Zhu + + + Geometry-dependent Ekman layer approximations on curved domains: L^{\infty} convergence + https://arxiv.org/abs/2512.18579 + arXiv:2512.18579v1 Announce Type: cross +Abstract: The Ekman boundary layer is a fundamental concept in fluid dynamics that describes fluid motion near boundaries affected by Earth's rotation. Most theoretical studies have simplified their analysis by assuming a planar boundary surface, resulting in limited exploration of structures with general smooth boundary conditions. Investigating the impact of boundary geometry in the Ekman boundary layer is essential, as initially suggested by J.L. Lions and further examined in Masmoudi's study [Comm. Pure Appl. Math. 53 (2000), 432-483] under small amplitude periodic boundary conditions. This paper clarifies how boundary geometry influences flow fields and characterizes its effects on near-boundary layer flow. We construct a class of multi-scale approximate solutions based on the boundary's geometric features and establish their convergence in the L^{\infty} framework. Our findings do not require a small-amplitude assumption, only an upper bound on the Gaussian curvature of the boundary surface. Notably, when the boundary is planar, our approach aligns with existing studies. Additionally, in the vanishing-viscosity limit, we derive a limiting-state system dependent on boundary geometric parameters. These contributions extend the theoretical understanding of boundary-layer interactions to general curved geometries and have possible applications in atmospheric, oceanic, and other geophysical flow contexts. + oai:arXiv.org:2512.18579v1 + math-ph + math.DS + math.MP + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Yifei Jia, Yi Du, Lihui Guo + + + Is the active suspension in a complex viscoelastic fluid more chaotic or more ordered? + https://arxiv.org/abs/2512.18580 + arXiv:2512.18580v1 Announce Type: cross +Abstract: The habitat of microorganisms is typically complex and viscoelastic. A natural question arises: Do polymers in a suspension of active swimmers enhance chaotic motion or promote orientational order? We address this issue by performing lattice Boltzmann simulations of squirmer suspensions in polymer solutions. At intermediate swimmer volume fractions, comparing to the Newtonian counterpart, polymers enhance polarization by up to a factor of 26 for neutral squirmers and 5 for pullers, thereby notably increasing orientational order. This effect arises from hydrodynamic feedback mechanism: squirmers stretch and align polymers, which in turn reinforce swimmer orientation and enhance polarization via hydrodynamic and steric interactions. The mechanism is validated by a positive correlation between polarization and a defined polymer-swimmer alignment parameter. Our findings establish a framework for understanding collective motion in complex fluids and suggest strategies for controlling active systems via polymer-mediated interactions. + oai:arXiv.org:2512.18580v1 + cond-mat.soft + physics.bio-ph + physics.comp-ph + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/publicdomain/zero/1.0/ + Yuan Zhou, Qingzhi Zou, Ignacio Pagonabarraga, Kaihuan Zhang, Kai Qi + + + Bell Nonlocality as a Covariance Obstruction in Locally Covariant Quantum Field Theory + https://arxiv.org/abs/2512.18603 + arXiv:2512.18603v1 Announce Type: cross +Abstract: Locally covariant algebraic quantum field theory (LCQFT) satisfies Einstein causality through microcausality and operational no-signalling, yet Bell-type correlations persist in entangled field states across spacelike regions. We demonstrate that this apparent tension reflects a fundamental covariance obstruction: no assignment of classical past variables can simultaneously be covariant under spacetime embeddings, screen off quantum correlations, and reproduce AQFT statistics. This obstruction is distinct from dynamical nonlocality or signalling violations. We formalize this as a no-go theorem in the category-theoretic framework of LCQFT, showing that Bell's notion of local causality -- requiring factorization conditioned on a common past -- is structurally incompatible with diffeomorphism covariance. The failure of Bell locality thus reflects not a breakdown of relativistic causality but the impossibility of embedding quantum correlations into a classical causal framework without introducing preferred foliations or non-covariant beables. This clarifies the conceptual status of nonlocality in relativistic quantum theory. + oai:arXiv.org:2512.18603v1 + gr-qc + physics.hist-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Joseph Samper Finberg + + + The Choice of Line Lengths in Multiline Thru-Reflect-Line Calibration + https://arxiv.org/abs/2512.18641 + arXiv:2512.18641v1 Announce Type: cross +Abstract: This paper presents an analysis and rigorous procedure for determining the optimal lengths of line standards in multiline thru-reflect-line (TRL) calibration of vector network analyzers (VNAs). The solution is obtained through nonlinear constrained optimization of the eigenvalue problem in multiline TRL calibration. Additionally, we propose a simplified approach for near-optimal length selection based on predefined sparse rulers. Alongside the length calculation, we discuss the required number of lines to meet bandwidth requirements. The sensitivity of the proposed procedure is evaluated numerically via Monte Carlo simulations, demonstrating that the derived lengths have lower uncertainty than those from existing industry standards. Practical examples are provided for various applications, including lossy and dispersive lines, as well as banded solutions for waveguides. + oai:arXiv.org:2512.18641v1 + eess.SP + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-sa/4.0/ + Ziad Hatab, Michael Gadringer, Wolfgang B\"osch + + + Collapse of Coulomb Bound States of Vector Bosons + https://arxiv.org/abs/2512.18691 + arXiv:2512.18691v1 Announce Type: cross +Abstract: Charged spin 1 (vector) particles behave very differently from electrons or scalars in a Coulomb field. For an infinitely heavy point-like nucleus their bound state wave functions fall to the centre, and embedding the system in a renormalisable electroweak-type theory does not remedy this short-distance pathology. We therefore solve the pure Coulomb problem for a finite nuclear radius $R$ and recover the point nucleus limit by letting $R\to 0$. This approach allows us to include the crucial Upsilon term in the wave equations, which for the point-like nucleus is proportional to delta(r) and was ignored in the previous calculations of the energy spectrum. Several unusual effects emerge: (i) The Upsilon term supports a tower of states located mainly inside the nucleus. As R -> 0 their number diverges, most lying in the negative energy continuum (energy epsilon < - m c^2). They trigger vacuum breakdown - particle-antiparticle pair creation that ultimately screens the nuclear charge. + (ii) Ordinary Sommerfeld-like states (with binding energy smaller m c^2) persist, but a finite fraction of each wave function leaks into the nucleus, even as R -> 0. + (iii) Charge density of a negatively charged vector particle changes sign in a vicinity of the nucleus and becomes positive charge density, whereas the Upsilon term ensures its density inside the nucleus remains negative. + (iv) For weak coupling, Z alpha << 1, yet with mR <Z alpha, the non-relativistic solution differs qualitatively from Schrodinger theory despite binding energies are well below m c^2; agreement is recovered only when Z alpha << mR. + These phenomena highlight the distinctive and subtle behaviour of spin-1 particles in the Coulomb field. + oai:arXiv.org:2512.18691v1 + hep-ph + nucl-th + physics.atom-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + V. V. Flambaum, H. B. Tran Tan + + + Extreme Nanoconfinement Reshapes the Self-Dissociation of Water + https://arxiv.org/abs/2512.18716 + arXiv:2512.18716v1 Announce Type: cross +Abstract: Water's ability to self-dissociate into H$_3$O$^+$ and OH$^-$ ions is central to acid-base chemistry and bioenergetics. Recent experimental advances have enabled the confinement of water down to the nanometre scale, even to the single-molecule limit, yet how this process is altered at the extreme nanoconfinement remains unclear. Using \emph{ab-initio} calculations and enhanced-sampling machine-learning potential molecular dynamics, we show that monolayer-confined water exhibits a markedly lower barrier to auto-dissociation than bulk water. Confinement restructures both intramolecular bonding and the intermolecular hydrogen-bond network, while enforcing quasi-2D dipolar correlations that amplify dielectric fluctuations. Our results imply that two-dimensional confined water could act as a \emph{superdielectric} medium and may exhibit \emph{superionic} behavior, as observed in recent experiments. These findings reveal confinement as a powerful route to enhanced proton activity, shedding light on geochemical niches, biomolecular environments, and nanofluidic systems where water's chemistry is fundamentally reshaped. + oai:arXiv.org:2512.18716v1 + cond-mat.mes-hall + cond-mat.mtrl-sci + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Chenyu Wang, Wanjian Yin, Ke Zhou + + + Quantifying the Emergence of Selection Prior to Biological Evolution + https://arxiv.org/abs/2512.18752 + arXiv:2512.18752v1 Announce Type: cross +Abstract: Selection is central to biological evolution, yet there has been no general experimental framework for quantifying selection in chemical systems before life. Here we demonstrate that selection in a prebiological chemical system can be directly quantified. Assembly Theory predicts that selection corresponds to a transition from undirected to directed exploration of chemical possibility space, measurable through the amount of Assembly, A, which integrates molecular assembly index with observed copy number. By analysing peptide ensembles produced under diverse polymerisation conditions, we show that undirected reactions explore sequence space almost uniformly, yielding exploration ratios of 0.85-0.95, whereas reactions influenced by evolved proteases generate markedly lower ratios (0.51-0.75) and elevated A, consistent with selective reinforcement of specific assembly pathways. Across multiple environments and amino-acid combinations, the exploration ratio and ensemble assembly A robustly distinguish directed from undirected exploration, establishing a general, experimentally tractable metric for detecting and measuring selection in chemical evolution. + oai:arXiv.org:2512.18752v1 + q-bio.MN + physics.bio-ph + q-bio.PE + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Michael Jirasek, Abhishek Sharma, Mary Wong, Jennifer Munro, Leroy Cronin + + + From Natural Language to Control Signals: A Conceptual Framework for Semantic Channel Finding in Complex Experimental Infrastructure + https://arxiv.org/abs/2512.18779 + arXiv:2512.18779v1 Announce Type: cross +Abstract: Modern experimental platforms such as particle accelerators, fusion devices, telescopes, and industrial process control systems expose tens to hundreds of thousands of control and diagnostic channels accumulated over decades of evolution. Operators and AI systems rely on informal expert knowledge, inconsistent naming conventions, and fragmented documentation to locate signals for monitoring, troubleshooting, and automated control, creating a persistent bottleneck for reliability, scalability, and language-model-driven interfaces. We formalize semantic channel finding-mapping natural-language intent to concrete control-system signals-as a general problem in complex experimental infrastructure, and introduce a four-paradigm framework to guide architecture selection across facility-specific data regimes. The paradigms span (i) direct in-context lookup over curated channel dictionaries, (ii) constrained hierarchical navigation through structured trees, (iii) interactive agent exploration using iterative reasoning and tool-based database queries, and (iv) ontology-grounded semantic search that decouples channel meaning from facility-specific naming conventions. We demonstrate each paradigm through proof-of-concept implementations at four operational facilities spanning two orders of magnitude in scale-from compact free-electron lasers to large synchrotron light sources-and diverse control-system architectures, from clean hierarchies to legacy environments. These implementations achieve 90-97% accuracy on expert-curated operational queries. + oai:arXiv.org:2512.18779v1 + cs.CL + physics.acc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Thorsten Hellert, Nikolay Agladze, Alex Giovannone, Jan Jug, Frank Mayet, Mark Sherwin, Antonin Sulc, Chris Tennant + + + Controllable Probabilistic Forecasting with Stochastic Decomposition Layers + https://arxiv.org/abs/2512.18815 + arXiv:2512.18815v1 Announce Type: cross +Abstract: AI weather prediction ensembles with latent noise injection and optimized with the continuous ranked probability score (CRPS) have produced both accurate and well-calibrated predictions with far less computational cost compared with diffusion-based methods. However, current CRPS ensemble approaches vary in their training strategies and noise injection mechanisms, with most injecting noise globally throughout the network via conditional normalization. This structure increases training expense and limits the physical interpretability of the stochastic perturbations. We introduce Stochastic Decomposition Layers (SDL) for converting deterministic machine learning weather models into probabilistic ensemble systems. Adapted from StyleGAN's hierarchical noise injection, SDL applies learned perturbations at three decoder scales through latent-driven modulation, per-pixel noise, and channel scaling. When applied to WXFormer via transfer learning, SDL requires less than 2\% of the computational cost needed to train the baseline model. Each ensemble member is generated from a compact latent tensor (5 MB), enabling perfect reproducibility and post-inference spread adjustment through latent rescaling. Evaluation on 2022 ERA5 reanalysis shows ensembles with spread-skill ratios approaching unity and rank histograms that progressively flatten toward uniformity through medium-range forecasts, achieving calibration competitive with operational IFS-ENS. Multi-scale experiments reveal hierarchical uncertainty: coarse layers modulate synoptic patterns while fine layers control mesoscale variability. The explicit latent parameterization provides interpretable uncertainty quantification for operational forecasting and climate applications. + oai:arXiv.org:2512.18815v1 + cs.LG + cs.AI + physics.ao-ph + physics.geo-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + John S. Schreck, William E. Chapman, Charlie Becker, David John Gagne II, Dhamma Kimpara, Nihanth Cherukuru, Judith Berner, Kirsten J. Mayer, Negin Sobhani + + + El Agente Cu\'antico: Automating quantum simulations + https://arxiv.org/abs/2512.18847 + arXiv:2512.18847v1 Announce Type: cross +Abstract: Quantum simulation is central to understanding and designing quantum systems across physics and chemistry. Yet it has barriers to access from both computational complexity and computational perspectives, due to the exponential growth of Hilbert space and the complexity of modern software tools. Here we introduce{\cinzel El Agente Cu\'antico}, a multi-agent AI system that automates quantum-simulation workflows by translating natural-language scientific intent into executed and validated computations across heterogeneous quantum-software frameworks. By reasoning directly over library documentation and APIs, our agentic system dynamically assembles end-to-end simulations spanning state preparation, closed- and open-system dynamics, tensor-network methods, quantum control, quantum error correction, and quantum resource estimation. The developed system unifies traditionally distinct simulation paradigms behind a single natural-language interface. Beyond reducing technical barriers, this approach opens a path toward scalable, adaptive, and increasingly autonomous quantum simulation, enabling faster exploration of physical models, rapid hypothesis testing, and closer integration between theory, simulation, and emerging quantum hardware. + oai:arXiv.org:2512.18847v1 + quant-ph + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Ignacio Gustin, Luis Mantilla Calder\'on, Juan B. P\'erez-S\'anchez, J\'er\^ome F. Gonthier, Yuma Nakamura, Karthik Panicker, Manav Ramprasad, Zijian Zhang, Yunheng Zou, Varinia Bernales, Al\'an Aspuru-Guzik + + + Optical SETI at ESO in the 2040s + https://arxiv.org/abs/2512.18903 + arXiv:2512.18903v1 Announce Type: cross +Abstract: The searches for other life and for intelligence are fundamental problems that science faces today. Most searches so far have been focused on radio, but optical laser communication is an alternative, well suited for a ground-based observatory. A project to search for artificial laser communications with the current and future extreme multiplexity spectroscopic facilities that ESO may develop by the 2040s is outlined. The monochromatic light is a clearly identifiable technosignature. The enormous corollary outreach potential of this initiative is underlined. + oai:arXiv.org:2512.18903v1 + astro-ph.IM + astro-ph.EP + physics.pop-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Valenitn D. Ivanov + + + Effect of the repulsion between twin granular impactors on crater's aspect ratio: preliminary findings + https://arxiv.org/abs/2512.18914 + arXiv:2512.18914v1 Announce Type: cross +Abstract: We study the role of repulsive granular interactions between identical intruders as they impact a granular bed. We demonstrate experimentally that repulsion does have a measurable effect in the aspect ratio of binary craters. Furthermore, we show that the protocol followed for the preparation of the granular bed plays a crucial role in the output of table-top experiments on doublet craters. + oai:arXiv.org:2512.18914v1 + cond-mat.soft + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + P. Altshuler, R. Pupo-Santos, A. Rivera, E. Altshuler + + + Needles in a haystack: using forensic network science to uncover insider trading + https://arxiv.org/abs/2512.18918 + arXiv:2512.18918v1 Announce Type: cross +Abstract: Although the automation and digitisation of anti-financial crime investigation has made significant progress in recent years, detecting insider trading remains a unique challenge, partly due to the limited availability of labelled data. To address this challenge, we propose using a data-driven networks approach that flags groups of corporate insiders who report coordinated transactions that are indicative of insider trading. Specifically, we leverage data on 2.9 million trades reported to the U.S. Securities and Exchange Commission (SEC) by company insiders (C-suite executives, board members and major shareholders) between 2014 and 2024. Our proposed algorithm constructs weighted edges between insiders based on the temporal similarity of their trades over the 10-year timeframe. Within this network we then uncover trends that indicate insider trading by focusing on central nodes and anomalous subgraphs. To highlight the validity of our approach we evaluate our findings with reference to two null models, generated by running our algorithm on synthetic empirically calibrated and shuffled datasets. The results indicate that our approach can be used to detect pairs or clusters of insiders whose behaviour suggests insider trading and/or market manipulation. + oai:arXiv.org:2512.18918v1 + cs.SI + physics.data-an + q-fin.CP + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Gian Jaeger, Wang Ngai Yeung, Renaud Lambiotte + + + Migration of gold atoms into a thiol-bonded molecular self-assembled monolayer, forming a cluster exhibiting a Coulomb staircase + https://arxiv.org/abs/2512.18931 + arXiv:2512.18931v1 Announce Type: cross +Abstract: Thiol-based self-assembled monolayers (SAMs) on gold surfaces are one of the fundamental building blocks of molecular electronics. The strong chemical affinity of the gold and sulfur (Au-S) enables the formation of close-packed SAMs, but it also has recently been found to create a dynamic interface where surface reconstruction can occur under illumination, even with ambient light. This reconstruction may facilitate migration of gold atoms, potentially leading to in-situ formation of gold clusters. However, research on this mechanism often centers on Au(111) crystalline surfaces and flicker-noise measurements. Electron transport in ensembles of molecules in lithographically defined junctions has remained largely unexplored at cryogenic temperatures. In this study, we observe single-electron phenomena characterized by reproducible Coulomb staircases across various long-chain alkanethiol SAMs, which fit the Coulomb-blockade theory of nm-sized metallic nanoparticles. We find no such current steps in samples with amine, rather than thiol, anchors. Additionally, we find that by adding a bipyridyl functional group, these phenomena can be harnessed for memristive switching and negative differential resistance. These findings indicate that the generally observed lack of reliability and reproducibility of molecular devices may be alleviated by using amine anchors instead of thiols to avoid nanoparticle effects. Conversely, the spontaneous formation of the nanoparticles could potentially be controlled and used to achieve useful functionalities, offering new pathways for designing multifunctional nanoelectronic components. + oai:arXiv.org:2512.18931v1 + cond-mat.mes-hall + physics.atm-clus + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Bingxin Li, Shanglong Ning, Chunyang Miao, Chenyang Guo, Gyu Don Kong, Xintai Wang, Victor I. Coldea, Yuqiao Li, Sam Harley, Oleg V. Kolosov, James Newson, Sam P. Jarvis, Ben J. Robinson, Mohammed Alzanbaqi, Ali Ismael, Colin J. Lambert, Hyo Jae Yoon, Jeremy J. Baumberg, Christopher J. B. Ford + + + Enhanced sinterability and in vitro bioactivity of diopside through fluoride doping + https://arxiv.org/abs/2512.19014 + arXiv:2512.19014v1 Announce Type: cross +Abstract: In this work, diopside (CaMgSi2O6) was doped with fluoride at a level of 1 mol.%, without the formation of any second phase, by a wet chemical precipitation method. The sintered structure of the synthesized nanopowders was studied by X-ray diffraction, Fourier transform infrared spectroscopy and field-emission scanning electron microscopy. Also, the samples' in vitro apatite-forming ability in a simulated body fluid was comparatively evaluated by electron microscopy, inductively coupled plasma spectroscopy and Fourier transform infrared spectroscopy. According to the results, the material's sinterability was improved by fluoride doping, as realized from the further development of sintering necks. It was also found that compared to the undoped bioceramic, a higher amount of apatite was deposited on the surface of the doped sample. It is concluded that fluoride can be considered as a doping agent in magnesium-containing silicates to improve biological, particularly bioactivity, behaviors. + oai:arXiv.org:2512.19014v1 + cond-mat.mtrl-sci + physics.app-ph + physics.bio-ph + physics.chem-ph + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1016/j.ceramint.2016.12.144 + Ceramics International, 43 (2017) 4680-4686 + E. Salahinejad, M. Jafari Baghjeghaz + + + The energy-speed relationship of quantum particles challenges Bohmian mechanics? + https://arxiv.org/abs/2512.19051 + arXiv:2512.19051v1 Announce Type: cross +Abstract: Recently, Sharoglazova et al. claimed to have proven a violation of the basic tenet of Bohmian mechanics, namely the phase-speed relation $\vec{v}(\vec{r},t)=\frac{\hbar}{m}\vec{\nabla}S(\vec{r},t)$. Here, $S(\vec{r},t)$ is the (real) phase of the wave function $\psi(\vec{r},t)=\rho^{\frac{1}{2}}(\vec{r},t)e^{iS(\vec{r},t)}$. In a nutshell, they have measured the speed of a claimed evanescent wave, which is real and therefore must have $\vec{\nabla}S=\vec{0}$. However, Fig. 2 clearly shows a density motion from one waveguide to the other, implying a nonzero density current, $\vec{j}(\vec{r},t)=\frac{\hbar}{2mi}\Im(\psi^*\vec{\nabla}\psi)$. If we combine this evidence with the mathematical identity $\vec{\nabla}S=\frac{m}{\rho}\vec{j}$, we should instead conclude that $\vec{\nabla}S\neq\vec{0}$. So, where does this apparent inconsistency come from? + oai:arXiv.org:2512.19051v1 + quant-ph + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + S. Di Matteo, C. Mazzoli + + + Quantum sensing of high-frequency gravitational waves with ion crystals + https://arxiv.org/abs/2512.19053 + arXiv:2512.19053v1 Announce Type: cross +Abstract: A detection method for high-frequency gravitational waves using two-dimensional ion crystals is investigated. Gravitational waves can resonantly excite the drumhead modes of the ion crystal, particularly the parity-odd modes. In the optical dipole force protocol, entanglement between the drumhead modes and the collective spins transfers the excitation of the drumhead modes to the rotation of the total spin. Furthermore, gravitational wave detection beyond the standard quantum limit becomes possible as a squeezed spin state is generated through this entanglement. The sensitivity gets better with a larger ions crystals as well as a larger number of the ions. Future realization of large ion crystals can significantly improve the sensitivity to gravitational waves in the 10 kHz to 10 MHz region. + oai:arXiv.org:2512.19053v1 + gr-qc + hep-ph + physics.atom-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Asuka Ito, Ryuichiro Kitano, Wakutaka Nakano, Ryoto Takai + + + Reactive near-field subwavelength microwave imaging with a non-invasive Rydberg probe + https://arxiv.org/abs/2512.19116 + arXiv:2512.19116v1 Announce Type: cross +Abstract: Non-invasive microwave field imaging--accurately mapping field distributions without perturbing them--is essential in areas such as aerospace engineering, biomedical imaging and integrated-circuit diagnostics. Conventional metal probes, however, inevitably perturb reactive near fields: they act as strong scatterers that drive induced currents and secondary radiation, remap evanescent components and thereby degrade both accuracy and spatial resolution, particularly in the reactive near-field regime that is most relevant to these applications. Here we demonstrate, to our knowledge for the first time, reactive near-field subwavelength imaging of microwave fields using the quantum non-demolition properties of Rydberg atoms, realized with a compact, non-invasive single-ended fibre-integrated Rydberg probe engineered to minimize field disturbance. The probe achieves an imaging resolution of {\unboldmath$\lambda/56$}, and the measured field distributions agree with full-wave simulations with structural similarity approaching unity, confirming both its subwavelength spatial resolution and its genuinely non-invasive character compared with conventional metal-based probes. Because the atomic sensor is intrinsically isotropic, the same device can faithfully image multi-dimensional field structures without orientation-dependent calibration. Our results therefore establish a general, non-invasive route to high-accuracy, subwavelength reactive near-field microwave imaging, with particular promise for applications such as chip-defect detection and integrated-circuit diagnostics, where even small perturbations by the probe can mask the underlying physics of interest. + oai:arXiv.org:2512.19116v1 + quant-ph + physics.app-ph + physics.atom-ph + physics.ins-det + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Chaoyang Hu, Mingyong Jing, Zongkai Liu, Shaoxin Yuan, Bin Wu, Yan Peng, Tingting Li, Wenguang Yang, Junyao Xie, Hao Zhang, Liantuan Xiao, Suotang Jia, Linjie Zhang + + + Aerogel RICH Counter at the Belle II Detector + https://arxiv.org/abs/2512.19146 + arXiv:2512.19146v1 Announce Type: cross +Abstract: We report on the design, operation, and performance of a novel proximity-focusing Ring Imaging Cherenkov (RICH) detector equipped with a multilayer focusing aerogel radiator, developed for the forward region of the Belle II spectrometer at the SuperKEKB $e^+e^-$ collider. The system achieves effective separation of charged pions, kaons, and protons across the full kinematic range of the experiment, from 0.5 GeV/c to 4 GeV/c. To date, the detector has successfully operated in data-taking, contributing to the collection and analysis of nearly 600/fb of Belle II $e^+e^-$ collision data. + oai:arXiv.org:2512.19146v1 + hep-ex + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + I. Adachi, N. Akopov, D. Augueste, J. Bonis, L. Burmistrov, S. Dey, R. Dolenec, G. Ghevondyan, R. Giordano, A. Hvala, T. Iijima, S. Iwata, H. Kakuno, G. Karyan, H. Kawai, T. Kohriki, T. Konno, S. Korpar, P. Krizan, S. Kurokawa, Y. Lai, A. Lozar, M. Mrvar, G. Nazaryan, S. Nishida, S. Ogawa, R. Pestotnik, I. Prudiiev, L. Santelj, A. Seljak, L. Senekovic, M. Shoji, K. Spenko, T. Sumiyoshi, M. Tabata, K. Uno, E. Waheed, M. Yonenaga, Y. Yusa + + + Limitations of Entangled Two-Photon Absorption detection + https://arxiv.org/abs/2512.19261 + arXiv:2512.19261v1 Announce Type: cross +Abstract: We introduce a method for determining the sensitivity of any given Entangled Two-Photon Absorption (ETPA) measurement. By modeling all signal and noise contributions to the measurement, we derive a single numerical value that describes the sensitivity of the ETPA measurement in G\"oppert-Mayer units. This allows us to directly compare vastly different experimental approaches and, determine whether ETPA will be detectable under the given conditions. Therefore, we can quantify the effect of any change to a given experimental apparatus and identify the ideal optimization pathway. + oai:arXiv.org:2512.19261v1 + quant-ph + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Ren\'e Pollmann, Franz Roeder, Christine Silberhorn, Benjamin Brecht + + + The asymptotic distribution of the likelihood ratio test statistic in two-peak discovery experiments + https://arxiv.org/abs/2512.19333 + arXiv:2512.19333v1 Announce Type: cross +Abstract: Likelihood ratio tests are widely used in high-energy physics, where the test statistic is usually assumed to follow a chi-squared distribution with a number of degrees of freedom specified by Wilks' theorem. This assumption breaks down when parameters such as signal or coupling strengths are restricted to be non-negative and their values under the null hypothesis lie on the boundary of the parameter space. Based on a recent clarification concerning the correct asymptotic distribution of the likelihood ratio test statistic for cases where two of the parameters are on the boundary, we revisit the the question of significance estimation for two-peak signal-plus-background counting experiments. In the high-energy physics literature, such experiments are commonly analyzed using Wilks' chi-squared distribution or the one-parameter Chernoff limit. We demonstrate that these approaches can lead to strongly miscalibrated significances, and that the test statistic distribution is instead well described by a chi-squared mixture with weights determined by the Fisher information matrix. Our results highlight the need for boundary-aware asymptotics in the analysis of two-peak counting experiments. + oai:arXiv.org:2512.19333v1 + hep-ex + physics.data-an + stat.AP + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://creativecommons.org/licenses/by/4.0/ + Clara Bertinelli Salucci, Hedvig Borgen Reiersrud, A. L. Read, Anders Kvellestad, Riccardo De Bin + + + Machine learning for the early classification of broad-lined Ic supernovae + https://arxiv.org/abs/2512.19386 + arXiv:2512.19386v1 Announce Type: cross +Abstract: Science is currently at an age where there is more data than we know how to deal with. Machine learning (ML) is an emerging tool that is useful in drawing valuable science out of incomprehensibly large datasets, identifying complex trends in data that are otherwise overlooked. Moreover, ML can potentially enhance the quality and quantity of scientific data as it is collected. This paper explores how a new ML method can improve the rate of classification of rare Ic-BL supernovae (SNe). New parameters called magnitude rates were introduced to train ML models to identify SNe Ic-BL in large datasets. The same methodology was applied to a population of SN Ia transients to see if the methodology could be reproducible with another SN class. Three magnitudes, three time differences, two magnitude rates and the second derivative of these rates were calculated using the first three available photometric data points in a single filter. Initial investigations show that the Random Forest algorithm provides a strong foundation for the early classifications SNe Ic-BL and SNe Ia. Testing this model again on an unseen dataset shows that the model can identify upward of 13% of the total true SN Ic-BL population, significantly improving upon current methods. By implementing a dedicated observation campaign using this model, the number of SN Ic-BL classified and the quality of early-time data collected each year will see considerable growth in the near future. + oai:arXiv.org:2512.19386v1 + astro-ph.HE + physics.data-an + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Laura Cotter, Antonio Martin Carrillo, Joseph Fisher, Gabriel Finneran, Gregory Corcoran, Jennifer Lebron + + + A Cartesian Cut-Cell Two-Fluid Method for Two-Phase Diffusion Problems + https://arxiv.org/abs/2512.19407 + arXiv:2512.19407v1 Announce Type: cross +Abstract: We present a Cartesian cut-cell finite-volume method for sharp-interface two-phase diffusion problems in static geometries. The formulation follows a two-fluid approach: independent diffusion equations are discretized in each phase on a fixed staggered Cartesian grid, while the phases are coupled through embedded interface conditions enforcing continuity of normal flux and a general jump law. Cut cells are treated by integrating the governing equations over phase-restricted control volumes and faces, yielding discrete divergence and gradient operators that are locally conservative within each phase. Interface coupling is achieved by introducing a small set of interfacial unknowns per cut cell on the embedded boundary; the resulting algebraic system involves only bulk and interfacial averages. A key feature of the method is the use of a reduced set of geometric information based solely on low-order moments (trimmed volumes, apertures and interface measures/centroids), allowing robust implementation without constructing explicitly cut-cell polytopes. The method supports steady (Poisson) and unsteady (diffusion) regimes and incorporates Dirichlet, Neumann, Robin boundary conditions and general jumps. We validate the scheme on one-, two- and three-dimensional mono- and diphasic benchmarks, including curved embedded boundaries, Robin conditions and strong property/jump contrasts. The results demonstrate the expected convergence behavior, sharp enforcement of interfacial laws and excellent conservation properties. Extensions to moving interfaces and Stefan-type free-boundary problems are natural perspectives of this framework. + oai:arXiv.org:2512.19407v1 + math.NA + cs.NA + physics.comp-ph + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Louis Libat, Can Sel\c{c}uk, Eric Ch\'enier, Vincent Le Chenadec + + + Machine Learning of Temperature-dependent Chemical Kinetics Using Parallel Droplet Microreactors + https://arxiv.org/abs/2512.19416 + arXiv:2512.19416v1 Announce Type: cross +Abstract: Temperature is a fundamental regulator of chemical and biochemical kinetics, yet capturing nonlinear thermal effects directly from experimental data remains a major challenge due to limited throughput and model flexibility. Recent advances in machine learning have enabled flexible modeling beyond conventional physical laws, but most existing strategies remain confined to surrogate models of end-point yields rather than full kinetic dynamics. Consequently, an end-to-end framework that unifies systematic kinetic data acquisition with machine learning based modeling has been lacking. In this paper, we present a unified framework that integrates droplet microfluidics with machine learning for the systematic analysis of temperature-dependent reaction kinetics. The platform is specifically designed to enable stable immobilization and long-term time-lapse imaging of thousands of droplets under dynamic thermal gradients. This configuration yields massively parallel time-resolved datasets across diverse temperature conditions that capture transient kinetics and provides particularly suitable inputs for training machine-learning models of reaction dynamics. Leveraging these datasets, we train Neural ODE models, which embed neural networks within differential equations to flexibly represent nonlinear temperature dependencies beyond conventional formulations. We demonstrate accurate prediction of enzymatic kinetics across diverse thermal environments, highlighting the robustness and versatility of the approach. Our framework bridges high-throughput experimental data acquisition with data-driven modeling, establishing a versatile foundation for enhanced predictive ability and rational analysis and design of temperature-sensitive biochemical processes. + oai:arXiv.org:2512.19416v1 + q-bio.QM + cs.SY + eess.SY physics.bio-ph - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - David Gao, Zeyuan Wang, Mihika Jain, Arnold J. T. M. Mathijssen, Ran Tao + Mamoru Saita, Yutaka Hori - Chronicle: "Foot of the iceberg" of Nobel Prize in Physics 2025: ILTPE and LTP contribution - https://arxiv.org/abs/2512.17050 - arXiv:2512.17050v1 Announce Type: cross -Abstract: The Nobel Prize in Physics 2025 has been awarded to John Clarke, John Martinis, and Michel Devoret for "the discovery of macroscopic quantum mechanical tunnelling and energy quantisation in an electric circuit". The paper explains the essence of their studies and shows in a historical context the importance of earlier research in superconductivity and quantum physics of macroscopic systems by other physicists, particularly, Ukrainian scientists, including employees of the B. Verkin Institute for Low Temperature Physics and Engineering of the NAS of Ukraine (ILTPE). The role of the Fizyka Nyzkykh Temperatur (FNT) journal issued by ILTPE in Kharkiv and its translation as AIP Low Temperature Physics (LTP) in dissemination of results of the theoretical and experimental studies in the field is emphasized as well. - oai:arXiv.org:2512.17050v1 - cond-mat.supr-con - physics.hist-ph - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Transformer-Based Approach to Enhance Positron Tracking Performance in MEG II + https://arxiv.org/abs/2512.19482 + arXiv:2512.19482v1 Announce Type: cross +Abstract: We developed a Transformer-based pattern recognition method for positron track reconstruction in the MEG II experiment. The model acts as a classifier to remove pileup hits in the MEG II drift chamber, which operates under a high pileup occupancy of 35 - 50 %. The trained model significantly improved hit purity, leading to enhancements in tracking efficiency and resolution by 15 % and 5 %, respectively, at a muon stopping rate of $5\times 10^7 \mu$/sec. This improvement translates into an approximately 10 % increase in the sensitivity of the $\mu\to e\gamma$ branching ratio measurement. + oai:arXiv.org:2512.19482v1 + hep-ex + physics.data-an + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - 10.1063/10.0039961 - Low Temp. Phys. 51, 1522-1524 (2025) - O. G. Turutanov + Lapo Dispoto, Fedor Ignatov, Atsushi Oya, Yusuke Uchiyama, Antoine Venturini - Accurate atomic correlation and total energies for correlation consistent effective core potentials II: Rb-Xe elements - https://arxiv.org/abs/2512.17063 - arXiv:2512.17063v1 Announce Type: cross -Abstract: We employ correlation-consistent effective core potentials (ccECPs) to perform exact or nearly exact correlation and total energy calculations for the fifth-row elements (Rb-Xe). Total energies are calculated using various correlated methods: configuration interaction (CI), coupled-cluster (CC) up to perturbative quadruple excitations whenever feasible, and stochastic quantum Monte Carlo (QMC) approaches. In order to estimate the energy at the complete basis set (CBS) limit, the basis sets are constructed systematically through aug-cc-p(C)VnZ for each ccECP and further extrapolated to the CBS limit within the corresponding methods. Kinetic energies are evaluated at the FCI/CISD level to provide insights into the electron density and localization of the ccECPs. We also provide data sets for widely used diffusion Monte Carlo (DMC) to quantify fixed-node biases with single-reference trial wavefunctions. These comprehensive benchmarks validate the accuracy of ccECPs within the CC, CI, and QMC methodologies, thus providing accurate and tested valence-only Hamiltonians for many-body electronic structure calculations. - oai:arXiv.org:2512.17063v1 + Computational Design of Metal-Free Porphyrin Dyes for Sustainable Dye-Sensitized Solar Cells Informing Energy Informatics and Decision Support + https://arxiv.org/abs/2512.19529 + arXiv:2512.19529v1 Announce Type: cross +Abstract: This study aims to evaluate the optoelectronic properties of metal free porphyrin-based D-$\pi$-A dyes via in-silico performance investigation notifying energy informatics and decision support. To develop novel organic dyes, three acceptor/anchoring groups and five donating groups were introduced to strategic positions of the base porphyrin structure, resulting in a total of fifteen dyes. The singlet ground state geometries of the dyes were optimized utilizing density functional theory (DFT) with B3LYP and the excited state optical properties were explored through time-dependent DFT (TD-DFT) using the PCM model with tetrahydrofuran (THF) as solvent. Both DFT and TD-DFT calculations were carried out using the 6-311G(d,p) basis set. The HOMO energy levels of almost all the modified dyes are lower than the redox potential of I$^-$/I$3^-$ and LUMO energy levels are higher than the conduction band of TiO$2$. The absorption maxima values ranged from 690.64 to 975.55 nm. The dye N1 using triphenylamine group as donor and p-ethynylbenzoic acid group as acceptor, showed optimum optoelectronic properties ($\Delta G{reg}=-9.73$ eV, $\Delta G{inj}=7.18$ eV, $V_{OC}=1.47$ V and $J_{SC}=15.03$ mA/cm$^2$) with highest PCE 14.37%, making it the best studied dye. This newly modified organic dye with enhanced PCE is remarkably effective for the dye-sensitized solar cells (DSSC) industry. Beyond materials discovery, this study highlights the role of high-performance computing in enabling predictive screening of dye candidates and generating performance indicators (HOMO-LUMO gaps, absorption spectra, charge transfer free energies, photovoltaic metrics). These outputs can serve as key parameters for energy informatics and system modelling. + oai:arXiv.org:2512.19529v1 cond-mat.mtrl-sci - physics.chem-ph physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 + cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Md Mahmudul Hasan, Chiara Bordin, Fairuz Islam, Tamanna Tasnim, Md. Athar Ishtiyaq, Md. Tasin Nur Rahim, Dhrubo Roy + + + Patlak Parametric Image Estimation from Dynamic PET Using Diffusion Model Prior + https://arxiv.org/abs/2512.19584 + arXiv:2512.19584v1 Announce Type: cross +Abstract: Dynamic PET enables the quantitative estimation of physiology-related parameters and is widely utilized in research and increasingly adopted in clinical settings. Parametric imaging in dynamic PET requires kinetic modeling to estimate voxel-wise physiological parameters based on specific kinetic models. However, parametric images estimated through kinetic model fitting often suffer from low image quality due to the inherently ill-posed nature of the fitting process and the limited counts resulting from non-continuous data acquisition across multiple bed positions in whole-body PET. In this work, we proposed a diffusion model-based kinetic modeling framework for parametric image estimation, using the Patlak model as an example. The score function of the diffusion model was pre-trained on static total-body PET images and served as a prior for both Patlak slope and intercept images by leveraging their patch-wise similarity. During inference, the kinetic model was incorporated as a data-consistency constraint to guide the parametric image estimation. The proposed framework was evaluated on total-body dynamic PET datasets with different dose levels, demonstrating the feasibility and promising performance of the proposed framework in improving parametric image quality. + oai:arXiv.org:2512.19584v1 + eess.IV + cs.CV + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Aqsa Shaikh, Omar Madany, Benjamin Kincaid, Lubos Mitas + Ziqian Huang, Boxiao Yu, Siqi Li, Savas Ozdemir, Sangjin Bae, Jae Sung Lee, Guobao Wang, Kuang Gong - An Asymptotic Approach for Modeling Multiscale Complex Fluids at the Fast Relaxation Limit - https://arxiv.org/abs/2512.17134 - arXiv:2512.17134v1 Announce Type: cross -Abstract: We present a new asymptotic strategy for general micro-macro models which analyze complex viscoelastic fluids governed by coupled multiscale dynamics. In such models, the elastic stress appearing in the macroscopic continuum equation is derived from the microscopic kinetic theory, which makes direct numerical simulations computationally expensive. To address this challenge, we introduce a formal asymptotic scheme that expands the density function around an equilibrium distribution, thereby reducing the high computational cost associated with the fully coupled microscopic processes while still maintaining the dynamic microscopic feedback in explicit expressions. The proposed asymptotic expansion is based on a detailed physical scaling law which characterizes the multiscale balance at the fast relaxation limit of the microscopic state. An asymptotic closure model for the macroscopic fluid equation is then derived according to the explicit asymptotic density expansion. Furthermore, the resulting closure model preserves the energy-dissipation law inherited from the original fully coupled multiscale system. Numerical experiments are performed to validate the asymptotic density formula and the corresponding flow velocity equations in several micro-macro models. This new asymptotic strategy offers a promising approach for efficient computations of a wide range of multiscale complex fluids. - oai:arXiv.org:2512.17134v1 + Topological Flux on a Context Manifold Generates Nonreciprocal Collective Dynamics + https://arxiv.org/abs/2512.19598 + arXiv:2512.19598v1 Announce Type: cross +Abstract: Non-reciprocal interactions, where the influence of agent $i$ on $j$ differs from that of $j$ on $i$, are fundamental in active and living matter. Yet, most models implement such asymmetry phenomenologically. Here we show that non-reciprocity can emerge from internal topology alone. Agents evolve on an internal ``context manifold'' coupled to a Chern-Simons gauge field. Because the gauge field is first order in time, it relaxes rapidly; eliminating it yields an effective transverse, antisymmetric interaction kernel that generically produces chiral waves, persistent vorticity, and irreversible state transitions. Numerical simulations reveal clear signatures of broken reciprocity: long-lived vortex cores, finite circulation, asymmetric information flow, and a nonzero reciprocity residual. The dynamics further exhibit pronounced hysteresis under parameter sweeps, demonstrating memory effects that cannot occur in reciprocal or potential-driven systems. These results identify Chern-Simons gauge fields as a minimal and universal source of directional influence and robust non-reciprocal collective behavior. + oai:arXiv.org:2512.19598v1 + nlin.AO math-ph math.MP - physics.comp-ph - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + physics.bio-ph + physics.soc-ph + Tue, 23 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Xuenan Li, Chun Liu, Di Qi + http://creativecommons.org/licenses/by/4.0/ + Jyotiranjan Beuria, Venkatesh H. Chembrolu - A Brief History and Outlook of Hadronic Physics in Indonesia - https://arxiv.org/abs/2512.17219 - arXiv:2512.17219v1 Announce Type: cross -Abstract: Hadronic physics has gradually emerged as one of the growing research frontiers in Indonesia, driven by efforts to better understand the properties of the strong interaction and the internal structure of hadrons from the fundamental principles of Quantum Chromodynamics. In the last few decades, Indonesian researchers have made significant contributions to developing various theoretical and phenomenological aspects of hadrons. In addition, on the experimental side, Indonesian scientists have participated in hadron experiment facilities overseas, such as the ALICE collaboration at CERN, which has strengthened the scientific activities and networks and has supported the training of young Indonesian researchers. In the present paper, we review Indonesian scientists' contributions to hadronic physics, highlight ongoing research directions in both experimental and theoretical, and outline strategies for future development toward integration into the international hadronic physics community. - oai:arXiv.org:2512.17219v1 - hep-ph - nucl-th - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Influence of Magnetic Order on Proximity-Induced Superconductivity in Mn Layers on Nb(110) from First Principles + https://arxiv.org/abs/2512.19634 + arXiv:2512.19634v1 Announce Type: cross +Abstract: We investigate the influence of magnetic order on the proximity-induced superconducting state in the Mn layers of a Mn-Nb(110) heterostructure by using a first-principles method. For this study, we use the recently developed Bogoliubov-de Gennes (BdG) solver for superconducting heterostructures [Csire et al., Phys. Rev. B 97, 024514 (2018)] within the first-principles calculations based on multiple scattering theory and the screened Korringa-Kohn-Rostoker (SKKR) Green's function method. In our calculations, we first study the normal-state density of states (DOS) in the single- and double-Mn-layer heterostructures, and calculate the induced magnetic moments in the Nb layers. Next, we compute the momentum-resolved spectral functions in the superconducting state for the heterostructure with a single Mn layer, and find bands crossing the Fermi level within the superconducting (SC) gap. We also study the SC state DOS in the single- and double-Mn-layer heterostructures and compare some of our results with experimental findings, revealing secondary gaps, plateau-like regions, and central V-shaped in-gap states within the bulk SC Nb gap that are magnetic-order-dependent. Finally, we compute the singlet and internally antisymmetric triplet (IAT) order parameters for each layer for both heterostructures, and find an order of magnitude difference in the induced singlet part of the SC order parameter in the Mn layer/s between the FM and AFM cases in favor of the AFM pairing with the maximum still being only 4.44% of the bulk Nb singlet order parameter value. We also find a negligible induced triplet part, yet comparable to the induced singlet values, indicating some singlet-triplet mixing in the Mn layer/s. + oai:arXiv.org:2512.19634v1 + cond-mat.supr-con + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Ahmad Jafar Arifi, Parada. T. P. Hutauruk, Terry Mart, Chalis Setyadi + Sohair ElMeligy, Bal\'azs \'Ujfalussy, Kyungwha Park - Machine Learning Assisted Parameter Tuning on Wavelet Transform Amorphous Radial Distribution Function - https://arxiv.org/abs/2512.17245 - arXiv:2512.17245v1 Announce Type: cross -Abstract: Understanding atomic structures is crucial, yet amorphous materials remain challenging due to their irregular and non-periodic nature. The wavelet-transform radial distribution function (WT-RDF) offers a physics-based framework for analyzing amorphous structures, reliably predicting the first and second RDF peaks and overall curve trends in both binary Ge 0.25 Se 0.75 and ternary Ag x(Ge 0.25 Se 0.75)100-x (x=5,10,15,20,25) systems. Despite these strengths, WT-RDF shows limitations in amplitude accuracy, which affects quantitative analyses such as coordination numbers. This study addresses the issue by optimizing WT-RDF parameters using a machine learning approach, producing the enhanced WT-RDF+ framework. WT-RDF+ improves the precision of peak predictions and outperforms benchmark ML models, including RBF and LSTM, even when trained on only 25 percent of the binary dataset. These results demonstrate that WT-RDF+ is a robust and reliable model for structural characterization of amorphous materials, particularly Ge-Se systems, and support the efficient design and development of phase-change thin films for next-generation electronic devices and components. - oai:arXiv.org:2512.17245v1 - cond-mat.mtrl-sci - cs.LG - physics.data-an - Mon, 22 Dec 2025 00:00:00 -0500 + Quantum Imaging of Birefringent Samples using Hong-Ou-Mandel Interference + https://arxiv.org/abs/2512.19637 + arXiv:2512.19637v1 Announce Type: cross +Abstract: Two-photon interference in a Hong-Ou-Mandel (HOM) interferometer can be used as a quantum sensing mechanism due to the sensitivity of the interference dip to perturbations of the photon indistinguishability. In particular, recent works have generalized this concept to microscopy setups, but the sensitivity to optical path differences constrains its application to samples with thickness variation typically below a few micrometers if tracking changes in the coincidences at a fixed delay. Extending the concept to polarization microscopy and circumventing this limitation, this manuscript explores the use of a narrowband photon pair source with coherence length >1 mm to broaden the HOM dip. Thus, realistic sample-thickness variations introduce negligible temporal distinguishability, and changes in coincidence rate at the dip centre are then dominated by sample-induced polarization effects. To compute the polarization rotation, we develop a statistical model for the interferometer, derive the Fisher information, and establish a maximum-likelihood estimator for the local fast-axis angle. Recording dip and baseline frames at each sample position via raster scanning, the experimental results validate the framework, agreeing with classical polarized-intensity images while demonstrating operation at a maximum-precision regime and insensitiveness to layer thickness. Overall, the approach enclosed provides a quantum-based quantitative imaging of birefringent structures, which can motivate further advantageous applications, including enhanced signal-to-noise ratio and lower damage imaging of photosensitive samples. + oai:arXiv.org:2512.19637v1 + quant-ph + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Deriyan Senjaya, Stephen Ekaputra Limantoro + http://creativecommons.org/licenses/by/4.0/ + Carolina Gon\c{c}alves, Tiago D. Ferreira, Catarina S. Monteiro, Nuno A. Silva - Deep Learning Enabled Nanoscale X-ray Photoemission Electron Microscopy (nanoXPEEM) - https://arxiv.org/abs/2512.17252 - arXiv:2512.17252v1 Announce Type: cross -Abstract: Understanding and manipulating two-dimensional materials for real-world applications remains challenging due to a lack of effective and high-throughput characterization techniques. Soft X-ray time-of-flight photoemission electron microscopy (XPEEM) provides element- and depth-sensitive information of materials and buried interfaces. However, chromatic and spherical aberrations cannot be corrected with electron-lens combinations. These aberrations, combined with astigmatism and space-charge effects, significantly degrade the spatial and energy resolutions. To overcome this limitation, we outline a spatial-attention based deep learning approach to automatically correct for these effects and attain nanometer resolution over the entire field-of-view (FoV). The combination of this corrective algorithm with XPEEM, termed as nanoXPEEM, establishes a new record of 48-nm spatial resolution with a 232-micrometer diameter FoV in the soft x-ray regime (700-1000 eV). nanoXPEEM provides unique spatial mapping of the element-specificity, depth-sensitivity, and local structure on the nanoscale. It can bridge the current gap to achieve angstrom (atomic) scale resolution. - oai:arXiv.org:2512.17252v1 - cond-mat.mtrl-sci - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 + Efficient Vision Mamba for MRI Super-Resolution via Hybrid Selective Scanning + https://arxiv.org/abs/2512.19676 + arXiv:2512.19676v1 Announce Type: cross +Abstract: Background: High-resolution MRI is critical for diagnosis, but long acquisition times limit clinical use. Super-resolution (SR) can enhance resolution post-scan, yet existing deep learning methods face fidelity-efficiency trade-offs. Purpose: To develop a computationally efficient and accurate deep learning framework for MRI SR that preserves anatomical detail for clinical integration. Materials and Methods: We propose a novel SR framework combining multi-head selective state-space models (MHSSM) with a lightweight channel MLP. The model uses 2D patch extraction with hybrid scanning to capture long-range dependencies. Each MambaFormer block integrates MHSSM, depthwise convolutions, and gated channel mixing. Evaluation used 7T brain T1 MP2RAGE maps (n=142) and 1.5T prostate T2w MRI (n=334). Comparisons included Bicubic interpolation, GANs (CycleGAN, Pix2pix, SPSR), transformers (SwinIR), Mamba (MambaIR), and diffusion models (I2SB, Res-SRDiff). Results: Our model achieved superior performance with exceptional efficiency. For 7T brain data: SSIM=0.951+-0.021, PSNR=26.90+-1.41 dB, LPIPS=0.076+-0.022, GMSD=0.083+-0.017, significantly outperforming all baselines (p<0.001). For prostate data: SSIM=0.770+-0.049, PSNR=27.15+-2.19 dB, LPIPS=0.190+-0.095, GMSD=0.087+-0.013. The framework used only 0.9M parameters and 57 GFLOPs, reducing parameters by 99.8% and computation by 97.5% versus Res-SRDiff, while outperforming SwinIR and MambaIR in accuracy and efficiency. Conclusion: The proposed framework provides an efficient, accurate MRI SR solution, delivering enhanced anatomical detail across datasets. Its low computational demand and state-of-the-art performance show strong potential for clinical translation. + oai:arXiv.org:2512.19676v1 + cs.CV + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 cross http://creativecommons.org/licenses/by/4.0/ - Aashwin Mishra, Daniel Ratner, Quynh Nguyen + Mojtaba Safari, Shansong Wang, Vanessa L Wildman, Mingzhe Hu, Zach Eidex, Chih-Wei Chang, Erik H Middlebrooks, Richard L. J Qiu, Pretesh Patel, Ashesh B. Jania, Hui Mao, Zhen Tian, Xiaofeng Yang - Microcomb-driven large-scale fully connected quantum network - https://arxiv.org/abs/2512.17318 - arXiv:2512.17318v1 Announce Type: cross -Abstract: Fully connected quantum networks enable simultaneously connecting every user to every other user and are the most versatile and robust networking architecture. However, the scalability of such networks remains great challenge for practical applications. Here we construct a large-scale fully connected quantum network founded on two-photon Hong-Ou-Mandel (HOM) interference, where user-to-user security is guaranteed even with untrusted network provider. Using integrated soliton microcomb (SMC) and photonic encoding chips, we realize precise massive parallel frequency generation and locking, high-visibility HOM interferences and measurement-device-independent (MDI) quantum key distribution. The proposed architecture enables a 200-user fully connected quantum network over 200 kilometers with strict information-theoretic security via untrusted network provider. The implemented networking architecture paves the way for realizing large-scale fully connected MDI quantum networks across metropolitan and intercity regions. - oai:arXiv.org:2512.17318v1 + Partition Function Estimation Using Analog Quantum Processors + https://arxiv.org/abs/2512.19685 + arXiv:2512.19685v1 Announce Type: cross +Abstract: We evaluate using programmable superconducting flux qubit D-Wave quantum annealers to approximate the partition function of Ising models. We propose the use of two distinct quantum annealer sampling methods: chains of Monte Carlo-like reverse quantum anneals, and standard linear-ramp quantum annealing. The control parameters used to attenuate the quality of the simulations are the effective analog energy scale of the J coupling, the total annealing time, and for the case of reverse annealing the anneal-pause. The core estimation technique is to sample across the energy spectrum of the classical Hamiltonian of interest, and therefore obtain a density of states estimate for each energy level, which in turn can be used to compute an estimate of the partition function with some sampling error. This estimation technique is powerful because once the distribution is sampled it allows thermodynamic quantity computation at arbitrary temperatures. On a $25$ spin $\pm J$ hardware graph native Ising model we find parameter regimes of the D-Wave processors that provide comparable result quality to two standard classical Monte Carlo methods, Multiple Histogram Reweighting and Wang-Landau. Remarkably, we find that fast quench-like anneals can quickly generate ensemble distributions that are very good estimates of the true partition function of the classical Ising model; on a Pegasus graph-structured QPU we report a logarithmic relative error of $7.6 \times 10^{-6}$, from $171,000$ samples generated using $0.2$ seconds of QPU time with an anneal time of $8$ nanoseconds per sample which is interestingly within the closed system dynamics timescale of the superconducting qubits. + oai:arXiv.org:2512.19685v1 quant-ph - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + cond-mat.dis-nn + cond-mat.stat-mech + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Fang-Xiang Wang, Sheng-Teng Zheng, Long Huang, Guo-We Zhang, Guang-Shu Wang, Wen-Jing Ding, Ze-Hao Wang, Shuang Wang, Zhen-Qiang Yin, Chang-Ling Zou, Brent E. Little, Guochao Wang, Lingxiao Zhu, Guang-Can Guo, Weiqiang Wang, Wenfu Zhang, Wei Chen, Zheng-Fu Han + Thinh Le, Elijah Pelofske - Influence of Pt/Ru ratios on the oxidation mechanism of MCrAlYTa coatings modified with Ptsingle bondRu overlays - https://arxiv.org/abs/2512.17384 - arXiv:2512.17384v1 Announce Type: cross -Abstract: This study investigates the influence of varying Pt/Ru ratios on the oxidation mechanism of NiCoCrAlYTa coatings with electrodeposited, vacuum-annealed Ptsingle bondRu overlays. Weight change measurements, scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used for high-temperature oxidation analyses, showing superior resistance with higher Pt contents. This was attributed to the creation of a denser, thinner, and more homogeneous layer of alumina (alpha-Al2O3) in the thermally-grown oxide (TGO) layer. On the contrary, an increase in Ru contents led to the development of other oxides and microcracks along with alumina in the TGO layer, undermining oxidation protection. The accommodation of Ti and Ta, in the minimally-deteriorative form of carbide, along with Y into the TGO layer with increasing Pt contents further enhanced oxidation resistance. In addition to the explored significant impact of the Pt/Ru ratio on oxide scale characteristics and oxidation resistance, the lower cost of Ru compared to Pt suggests the potential for designing cost-effective systems through optimized Pt/Ru ratios and microstructural engineering. - oai:arXiv.org:2512.17384v1 + 2D coherent spectroscopy signatures of exciton condensation in Ta$_2$NiSe$_5$ + https://arxiv.org/abs/2512.19689 + arXiv:2512.19689v1 Announce Type: cross +Abstract: We show that the nonlinear optical response probed by two-dimensional coherent spectroscopy (2DCS) can discriminate between excitonic and lattice driven order. In the excitonic regime of a realistic model of Ta$_2$NiSe$_5$, the third order 2DCS signals are strongly enhanced by the condensate's amplitude and phase modes, with negligible contributions from single-particle excitations. In the linear optical response, in contrast, single-particle and collective-mode contributions overlap. With increasing electron-phonon coupling, the amplitude mode contribution to 2DCS initially remains robust, but then drops rapidly and remains small in the phonon-dominated regime -- even in systems with large order parameter. 2DCS also aids the detection of the massive relative phase mode, which is analogous to the Leggett mode in superconductors. Our analysis, based on the time-dependent Hartree-Fock approach, demonstrates that 2DCS can track the emergence of the symmetry-broken state and the crossover from Coulomb-driven to phonon-driven order. + oai:arXiv.org:2512.19689v1 + cond-mat.str-el cond-mat.mtrl-sci - physics.app-ph - physics.atom-ph - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1016/j.surfcoat.2025.132224 - Surface and Coatings Technology, 510 (2025) 132224 - Majid Hosseinzadeh, Erfan Salahinejad + http://creativecommons.org/licenses/by/4.0/ + Jiyu Chen, Jernej Mravlje, Denis Gole\v{z}, Philipp Werner - Comparative analysis of electrodeposited Pt, Ru and Pt-Ru overlays for high-temperature oxidation protection - https://arxiv.org/abs/2512.17392 - arXiv:2512.17392v1 Announce Type: cross -Abstract: Platinum (Pt) and ruthenium (Ru), both members of the platinum-group metals (PGMs), are renowned for their exceptional resistance to corrosion, oxidation, and high temperatures, making them promising candidates for advanced high-temperature applications. This study investigates the direct current (DC) electrodeposition of Pt, Ru, and a binary Pt-Ru alloy onto NiCoCrAlYTa-coated single-crystal superalloy CMSX-4, along with their vacuum annealing and respective effects on the isothermal oxidation behavior of the system at 1100 {\deg}C. All the electrodeposited overlays demonstrated substantial enhancement in oxidation resistance. However, Pt exhibited the highest protection efficiency, Ru the least, and the Pt-Ru alloy provided an intermediate level of performance. Microscopic and X-ray diffraction analyses revealed that the competitive formation of protective {\alpha}-Al2O3 and spinel NiAl2O4 phases on the coated surfaces played a crucial role in determining the oxidation resistance, driven by atomic interactions between the elements in the NiCoCrAlYTa bond coat and the overlay metals. Despite Ru's relatively lower oxidation resistance compared to Pt, its significantly lower cost offers potential advantages in cost-sensitive, high-temperature applications. These findings provide valuable insights into optimizing Pt-group metal coatings for durability in high-performance systems. - oai:arXiv.org:2512.17392v1 - cond-mat.mtrl-sci - physics.app-ph - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1016/j.surfcoat.2024.131685 - Surface and Coatings Technology, 496 (2025) 131685 - Majid Hosseinzadeh, Erfan Salahinejad + Relativistic and Gravitational transformations in Electrochemistry and NMR spectroscopy + https://arxiv.org/abs/1808.09350 + arXiv:1808.09350v5 Announce Type: replace +Abstract: A relativistic transformation of the electrode potential has been derived to account for time dilation effects in electrode processes. This newly formulated Lorentz transformation is interpreted through the generation of spin-2 boson gravitons, originating from the fusion of spin-1 boson virtual photons, which subsequently escape into higher dimensions. Gravitational transformations of the electrode potential have also been derived, explaining the observed decrease in cell potential under stronger gravitational fields. The reduction in electrode potential near a gravitational source is attributed to a greater flux of gravitons escaping into higher dimensions in stronger gravitational fields compared to weaker ones. Similarly, the potential energy associated with the spin of magnetically active nuclei in an applied magnetic field, as observed in NMR spectroscopy, is shown to be Lorentz variant. This provides a mathematical demonstration that the Hamiltonian describing the energy of such nuclei is also Lorentz variant. The relativistic and gravitational transformations of both the electrode potential and the spin-related potential energy in magnetic fields are shown to be analogous. + oai:arXiv.org:1808.09350v5 + physics.gen-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Mirza Wasif Baig - Eliminating the irregular surface layer of anodically-grown Ni-Ti-O nanopore arrays in a two-stage anodization - https://arxiv.org/abs/2512.17397 - arXiv:2512.17397v1 Announce Type: cross -Abstract: Nanopores (NPs) grown by anodizing can be partially hidden beneath a relatively compact surface oxide layer, which limits the volumetric surface area of these nanostructures. In this work, nitinol (NiTi) alloy was anodized in an electrolyte containing ethylene glycol, water, and sodium chloride in static and stirred electrolyte stages with the aim of removing the irregular surface array while achieving a thick NP layer. Electron micrographs showed that anodization in the static electrolyte provides a controlled thickness of NP layers covered by an irregular surface layer. In contrast, anodizing in the stirred electrolyte reduced the thickness and the degree of irregularity, which were controlled by the different kinetics of dissolution at the tops, perimeters and bottoms of NPs. To benefit simultaneously from the thickness and regularity of the oxide layers, two-stage anodizing under static and then stirred electrolyte conditions was found to be effective. Following a 30 min anodization in the static electrolyte, anodizing for 30 min under the stirred conditions provided the highest regularity in the oxide array, resulting in NPs of almost 40 nm and 11 {\mu}m in diameter and layer thickness, respectively. Two-stage anodizing under static then stirred electrolyte conditions is proposed in order to promote NP structures for applications demanding higher surface areas. - oai:arXiv.org:2512.17397v1 - cond-mat.mtrl-sci - physics.app-ph - physics.bio-ph - physics.chem-ph - physics.med-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1016/j.surfcoat.2020.126707 - Surface and Coatings Technology, 405 (2021) 126707 - S. A. Mousavi, A. Moshfeghi, F. Davoodian, E. Salahinejad + Strategy evolution on temporal hypergraphs + https://arxiv.org/abs/2306.01300 + arXiv:2306.01300v3 Announce Type: replace +Abstract: Individuals interact and cooperate in structured systems. Many studies represent this structure using static networks, where each link represents a permanent connection between two nodes. However, real interactions are generally not time-invariant and are often not pairwise. Recently, progress has been made in modeling higher-order interactions using hypergraphs, where a link may connect more than two individuals. Here, we study cooperation on temporal hypergraphs, capturing the time-varying, higher-order interactions seen in empirical systems. We find that temporal hypergraphs can promote cooperation compared with static networks, and the latter may even underestimate the cooperation-boosting effects of constrained, local interactions. We further show that cooperation can be facilitated by temporal hypergraphs with sparse components and higher-order interactions. Importantly, when the size of group interactions (hyperedges) is comparable to the population size, relatively small hyperedge sizes best facilitate cooperation. Synthetic and empirical hypergraphs alike affirm our findings, illuminating how temporal, higher-order interactions profoundly shape the evolution of cooperation. + oai:arXiv.org:2306.01300v3 + physics.soc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + Xiaochen Wang, Lei Zhou, Alex McAvoy, Zhenglong Tian, Aming Li - Magnetic, Structural, and Electronic Properties of CrOCl with the PBE Functional - https://arxiv.org/abs/2512.17405 - arXiv:2512.17405v1 Announce Type: cross -Abstract: CrOCl is a van der Waals-layered insulator with an antiferromagnetic ground state, making it a promising platform for exfoliation and the exploration of low-dimensional magnetism. An accurate ab initio description is therefore essential. Previous density-functional studies have shown that DFT+$U$ calculations may erroneously favor ferromagnetic order depending on the choice of parametrization, an issue that cannot be remedied by simply adjusting the value of $U$. Here, we demonstrate that an explicit Hubbard correction is unnecessary: the PBE functional correctly reproduces the AFM ground state while simultaneously improving the description of structural properties. Moreover, PBE provides a reliable account of the electronic structure. These findings clarify the role of correlation effects in CrOCl and identify PBE as a robust starting point for future ab initio studies of CrOCl-based materials. - oai:arXiv.org:2512.17405v1 - cond-mat.mtrl-sci + Monitoring of water volume in a porous reservoir using seismic data: Validation of a numerical model with a field experiment + https://arxiv.org/abs/2312.14605 + arXiv:2312.14605v4 Announce Type: replace +Abstract: As global groundwater levels continue to decline rapidly, there is a growing need for advanced techniques to monitor and manage aquifers effectively. This study focuses on validating a numerical model using seismic data from a small-scale experimental setup designed to estimate water volume in a porous reservoir. Expanding on previous work with synthetic data, we analyze seismic data acquired from a controlled experimental site in Laukaa, Finland. By employing neural networks, we directly estimate water volume from seismic responses, bypassing the traditional need for separate determinations, for example, of reservoir water-table level and porosity. The study models wave propagation through a coupled poroviscoelastic-viscoelastic medium using a three-dimensional discontinuous Galerkin method. The proposed methodology is validated against experimental data, aiming to improve precision in mapping current water volumes and contributing to the development of sustainable groundwater management practices. + oai:arXiv.org:2312.14605v4 physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + physics.geo-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Brahim Marfoua, Mohammad Amirabbasi, Marcus Ekholm + Mahnaz Khalili, Bojan Brodic, Peter G\"oransson, Suvi Heinonen, Jan S. Hesthaven, Antti Pasanen, Marko Vauhkonen, Rahul Yadav, Timo L\"ahivaara - Bandgap Engineering for Efficient Perovskite Solar Cells Under Multiple Color Temperature Indoor Lighting - https://arxiv.org/abs/2512.17479 - arXiv:2512.17479v1 Announce Type: cross -Abstract: Perovskite indoor photovoltaics (PIPVs) are emerging as a transformative technology for low-light intensity energy harvesting, owing to their high power conversion efficiencies (PCEs), low-cost fabrication, solution-processability, and compositionally tunable band gaps. In this work, methylammonium-free perovskite absorbers were compositionally engineered to achieve band gaps of 1.55, 1.72, and 1.88 eV, enabling matching the spectral photoresponse with the indoor lighting. Devices based on a scalable mesoscopic n-i-p architecture were systematically evaluated under white LED illumination across correlated color temperatures (3000-5500 K) and light intensities from 250 to 1000 lux with active area of 1 cm2. The 1.72 eV composition exhibited the most promising performance across different light intensities and colors, achieving PCEs of 35.04 % at 1000 lux and 36.6 % at 250 lux, with a stable device operation of over 2000 hours. On the other hand, the 1.88 eV band-gap variant reached a peak PCE of 37.4 % under 250 lux (5500 K), however performance trade-offs were observed across the different color lights LEDs. Our combined experimental and theoretical optical-electrical simulations suggest that decreasing trap-assisted recombination in wide-bandgap compositions may further improve PIPV performance across the different illumination conditions. In contrast, devices with 1.55 eV band gap underperformed in such conditions due to suboptimal spectral overlap and utilization. These findings establish bandgap optimization and device architecture as key design principles for high-efficiency, stable PIPVs, advancing their integration into self-powered electronic systems and innovative indoor environments. - oai:arXiv.org:2512.17479v1 - cond-mat.mtrl-sci - physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Majority voting is not good for heaven or hell, with mirrored performance + https://arxiv.org/abs/2401.00592 + arXiv:2401.00592v5 Announce Type: replace +Abstract: Within the ViSE (Voting in Stochastic Environment) model, we study the effectiveness of majority voting in various environments. As shown by the pit-of-losses paradox identified in previous work, majority decisions in apparently hostile environments tend to reduce the capital of society. In such cases, the simple social decision rule of ``rejecting all proposals without voting'' outperforms majority voting. In this paper, we identify another pit of losses appearing in favorable environments; here, the simple social decision rule of ``accepting all proposals without voting'' is superior to majority voting. We prove that, under a version of simple majority called symmetrized majority and under the antisymmetry of the voting body, this second pit of losses is a mirror image of the one arising in hostile environments, and we explain this phenomenon. Technically, we consider a voting society consisting of individualists who support all proposals that increase their personal capital and a group (or groups) whose members vote to increase their group's wealth. According to the key lemma, the expected capital gain of each agent under the social decision rule when the random gain generator is $X$ with mean $\mu>0$ exceeds their expected gain under the reflected generator $-X$ by exactly $\mu$. This extends to location-scale families of generators with distributions symmetric about their mean. This result reveals a mirror symmetry in the performance of the symmetrized majority rule relative to a baseline rule. The baseline rule accepts all proposals in favorable environments and rejects them in unfavorable (hostile) ones. + oai:arXiv.org:2401.00592v5 + physics.soc-ph + cs.GT + math.OC + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Pavel Chebotarev, Vadim Afonkin + + + Calculated state-of-the art results for solvation and ionization energies of thousands of organic molecules relevant to battery design + https://arxiv.org/abs/2411.00994 + arXiv:2411.00994v2 Announce Type: replace +Abstract: We present high-quality reference data for two fundamentally important groups of molecular properties related to a compound's utility as a lithium battery electrolyte. The first property is energy changes associated with charge excitations of molecules, namely ionization potential and electron affinity. They were estimated for 7000 randomly chosen molecules with up to 9 non-hydrogen atoms C, N, O, and F (QM9 dataset) using the DH-HF, DF-HF-CABS, PNO-LMP2-F12, and PNO-LCCSD(T)-F12 methods as implemented in the Molpro software, and the aug-cc-pVTZ basis set. Additionally, we provide the corresponding atomization energies at these levels of theory, as well as the CPU time and disk space used during the calculations. The second property is solvation energies for 39 different solvents, which we estimate for 18361 molecules connected to battery design (Electrolyte Genome Project dataset), 309463 randomly chosen molecules with up to 17 non-hydrogen atoms C, N, O, S, and halogens (GDB17 dataset), as well as 88418 atoms-in-molecules of the ZINC database of commercially available compounds and 37772 atoms-in-molecules of GDB17. For these calculations we used the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) method; we additionally provide estimates of gas-phase atomization energies, as well as information about conformers considered during the COSMO-RS calculations, namely coordinates, energies, and dipole moments. + oai:arXiv.org:2411.00994v2 + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - Miqad S. Albishi, Faisal I. Alabdulkarem, George Perrakis, Tariq F. Alhuwaymel, Ala H. Sabeeh, Abdullah S. Alharbi, Naif R. Alshamrani, Ibrahim H. Khawaji, Nikolaos Tzoganakis, Majed M. Aljomah, Dimitris Tsikritzis, Sami A. Alhusaini, Abdullah Aljalalah, Kadi S. AlShebl, Ali Alanzi, Abrar Bin Ajaj, Fay M. Alotaibi, Hamad Albrithen, Konstantinos Petridis, Maria Kafesaki, Emmanuel Kymakis, George Kakavelakis, Essa A. Alharbi + 10.1088/2632-2153/adf595 + Jan Weinreich, Konstantin Karandashev, Daniel Jose Arismendi Arrieta, Kersti Hermansson, O. Anatole von Lilienfeld - Autonomous Picosecond-Precision Synchronization in Measurement-Device-Independent Quantum Key Distribution - https://arxiv.org/abs/2512.17510 - arXiv:2512.17510v1 Announce Type: cross -Abstract: Measurement-device-independent quantum key distribution (MDI-QKD) eliminates detector side-channel attacks by relocating all measurements to an untrusted intermediate node. However, its practical implementation critically relies on picosecond-level temporal synchronization between spatially separated users. In this work, we present a physically motivated autonomous synchronization algorithm for fiber-based MDI-QKD networks that does not require auxiliary optical channels or shared clock references. The method exploits round-trip optical pulse propagation and statistical signal detection in the presence of Gaussian noise. We derive analytical expressions for false-alarm probabilities, quantify detection reliability, and demonstrate through numerical modeling that synchronization accuracy better than 10~ps is achievable for channel lengths up to 100~km with realistic optical power levels. The proposed approach improves the scalability and robustness of MDI-QKD architectures and is directly applicable to metropolitan and backbone quantum networks. - oai:arXiv.org:2512.17510v1 - quant-ph - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - A. P. Pljonkin + Thermodynamic Coupling of Mass and Electromagnetic Fields: Entropic Origin of Parity Asymmetry and the Meissner Effect + https://arxiv.org/abs/2411.16798 + arXiv:2411.16798v2 Announce Type: replace +Abstract: We develop a thermodynamic framework that couples mass dynamics, described by the Newton- Gibbs-van der Waals formalism, with electromagnetic fields beyond the scope of classical Maxwell theory. Classical Newtonian mechanics does not capture density evolution in the momentum balance, while the standard Maxwell equations neglect the contribution of the curl component of the electric field associated with moving charges. Building on an alternative understanding on entropy, we develop a generalized theory for electrodynamics governed by entropy-production constraints. The resulting framework yields a modified Maxwell stress tensor that incorporates the moving-charge contribution, leading to intrinsic parity asymmetry in electromagnetic forces. The theory naturally reproduces key features of superconductivity, including the Meissner effect, and reduces to the conventional Maxwell-Faraday and Maxwell-Ampere equations in an appropriate limit. This entropic formulation provides a unified thermodynamic basis for mass-field coupling and reveals new physical consequences arising from motion-induced electromagnetic effects. + oai:arXiv.org:2411.16798v2 + physics.class-ph + math-ph + math.MP + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + Fei Wang - Design of a minimal, allosteric, and ATPase-like machine using mechanical linkages - https://arxiv.org/abs/2512.17597 - arXiv:2512.17597v1 Announce Type: cross -Abstract: ATPases cyclically convert chemical energy in the form of ATP gradients into directed motion inside cells. To function, ATPases rely on allosteric communication between at least two binding sites, an internal signaling mechanism that is not well understood. Here, we model an ATPase-like machine by using a system of mechanical linkages to recreate negative allosteric coupling between two binding sites and generate cycles in which the sites alternate occupancy. The ATPase analog has two mechanical degrees of freedom and two discretized binding sites: one for the ATP, Pi and ADP analogs, and one for an allosteric effector analog. The geometry of the ATPase analog allows stepwise binding reactions at each site to capture the two degrees of freedom in a mutually exclusive way. Consequently, the enzyme interconverts between multiple rigid and partially rigid forms, such that neither site can be fully bound when both sites are occupied. Two mechanisms work together to generate an enzymatic cycle: one, in which the tighter-binding ATP analog can bind and displace the effector from the enzyme; and a second, in which flexibility introduced by splitting the ATP analog into two pieces (catalysis) allows the effector to rebind and displace the products (ADP analog). We show that cleavage (forward catalysis) and ligation (reverse catalysis) alter the rigidity of the enzyme complex equivalently to binding and dissociation, respectively, but must do so more slowly for effective cycling to take place. Simple designs for synthetic systems that mimic ATPase monomers can be derived from this work. - oai:arXiv.org:2512.17597v1 - q-bio.MN - cond-mat.soft - physics.bio-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Power Laws for the Thermal Slip Length of a Liquid/Solid Interface From the Structure and Frequency Response of the Contact Zone + https://arxiv.org/abs/2412.05443 + arXiv:2412.05443v4 Announce Type: replace +Abstract: The newest and most powerful electronic chips for applications like artificial intelligence generate so much heat that liquid based cooling has become indispensable to prevent breakdown from thermal runaway effects. While cooling schemes like microfluidic networks or liquid immersion are proving effective for now, further progress requires tackling an age old problem, namely the intrinsic thermal impedance of the liquid/solid (L/S) interface, quantified either by the thermal boundary resistance or thermal slip length. While there exist well known models for estimating bounds on the thermal impedance of a superfluid/metal interface, no analytic models nor experimental data are available for normal liquid/solid interfaces. Researchers therefore rely on non-equilibrium molecular dynamics simulations to gain insight into phonon transfer at the L/S interface. Here we explore correlated order and motion within the L/S contact zone in an effort to extract general scaling relations for the thermal slip length in Lennard-Jones (LJ) systems. We focus on the in-plane structure factor and dominant vibrational frequency of the first solid and liquid layer for 180 systems. When scaled by the temperature of the liquid contact layer and characteristic LJ interaction distance, the data collapse onto two power law equations, one quantifying the reduction in thermal impedance from enhanced in-plane translational order and the other from enhanced frequency matching in the contact zone. More generally, these power law relations highlight the critical role of surface acoustic phonons, an area of focus which may prove more useful to development of analytic models and instrumentation for validating the relations proposed. + oai:arXiv.org:2412.05443v4 + physics.comp-ph + cond-mat.mes-hall + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - Tosan Omabegho + 10.1103/ztng-519w + Hiroki Kaifu, Sandra M. Troian - Gutenberg-Richter-like relations in physical systems - https://arxiv.org/abs/2512.17615 - arXiv:2512.17615v1 Announce Type: cross -Abstract: We analyze regional earthquake energy statistics from the Southern California and Japan seismic catalogs and find scale-invariant energy distributions characterized by an exponent $\tau \simeq 1.67$. To quantify how closely scale-invariant dynamics with different exponent values resemble real earthquakes, we generate synthetic energy distributions over a wide range of $\tau$ under conditions of constant activity. Earthquake-like behavior, in a broad sense, is obtained for $1.5 \leqslant \tau < 2.0$. When energy variations are further restricted to be within a factor of ten relative to real earthquakes, the admissible range narrows to $1.58 \leqslant \tau \leqslant 1.76$. We identify the physical mechanisms governing the dynamics in the different regimes: fault dynamics characterized by a balance between slow energy accumulation and release through scale-free events in the earthquake-like regime; externally supplied energy relative to a slowly driven fault for $\tau < 1.5$; and dominance of small events in the energy budget for $\tau > 2$ - oai:arXiv.org:2512.17615v1 - cond-mat.stat-mech - cond-mat.dis-nn - physics.geo-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + WaveOrder: A differentiable wave-optical framework for scalable biological microscopy with diverse modalities + https://arxiv.org/abs/2412.09775 + arXiv:2412.09775v3 Announce Type: replace +Abstract: Correlative computational microscopy can accelerate imaging and modeling of cellular dynamics by relaxing trade-offs inherent to dynamic imaging. Existing computational microscopy frameworks are either specialized or overly generic, limiting use to fixed configurations or domain experts. We introduce WaveOrder, a generalist wave-optical framework for imaging the architectural order of biomolecules. WaveOrder reconstructs diverse specimen properties from multi-channel acquisitions, with or without fluorescence. It provides a unified representation of linear optical properties and differentiable physics-based image formation models spanning widefield, confocal, light-sheet, and oblique label-free geometries. WaveOrder uses physics-informed ML to auto-tune model parameters and solve blind shift-variant restoration problems. This open-source, PyTorch-based framework enables scalable quantitative imaging across scales from organelles to adult zebrafish, and improves restoration of cellular structures in high-throughput experiments. We validate WaveOrder on diverse imaging applications, demonstrating its ability to recover biomolecular structure beyond the limits of existing approaches. + oai:arXiv.org:2412.09775v3 + physics.optics + cs.CV + q-bio.QM + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-sa/4.0/ + Talon Chandler, Ivan E. Ivanov, Gabriel Sturm, Sheng Xiao, Xiang Zhao, Alexander Hillsley, Allyson Quinn Ryan, Ziwen Liu, Sricharan Reddy Varra, Ilan Theodoro, Eduardo Hirata-Miyasaki, Deepika Sundarraman, Amitabh Verma, Madhurya Sekhar, Chad Liu, Soorya Pradeep, See-Chi Lee, Shannon N. Rhoads, Maria Clara Zanellati, Sarah Cohen, Carolina Arias, Manuel D. Leonetti, Adrian Jacobo, Keir Balla, Lo\"ic A. Royer, Shalin B. Mehta + + + The effect of split endcaps on the flow dynamics in a tall Taylor-Couette setup + https://arxiv.org/abs/2503.08875 + arXiv:2503.08875v2 Announce Type: replace +Abstract: The effects of axial boundaries, or endcaps are of fundamental interest in many Taylor-Couette (TC) flow experiments. A main challenge in those experiments has been to minimize these effects, which can substantially alter the flow structure compared to the axially unbounded idealized case. Therefore, understanding and disentangling the influence of endcaps on the TC flow dynamics is essential for the unambiguous interpretation of experimental results, particularly when other dynamical processes (instabilities) in TC flows are involved. In this paper, we study the hydrodynamic evolution of a quasi-Keplerian TC flow in the presence of split endcaps for high Reynolds numbers, $Re$, up to $2\times 10^5$, which are larger than those considered in related previous studies. At these $Re$, the flow deviates from the ideal TC flow profile without endcaps, resulting in about $15\%$ deviation in angular velocity at the mid-height of the cylinders. Aside from turbulent fluctuations caused by shearing instability near the endcaps, the bulk flow remains nearly axially independent and exhibits overall Rayleigh-stability. We characterize the scalings of the Ekman and Stewartson layer sizes with $Re$ as well as examine the effect of the ratio of the outer to inner cylinders' angular velocities on the flow. The implications of these findings for ongoing magnetorotational instability (MRI) experiments based on the similar axially bounded TC setup are also discussed. Specifically, it is shown that when imposing a constant axial magnetic field in all the considered configurations, the flow profile modified by the endcaps lowers the critical threshold for the onset of MRI that in turn can facilitate its emergence and detection in those experiments. + oai:arXiv.org:2503.08875v2 + physics.flu-dyn + astro-ph.HE + astro-ph.SR + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - K. Duplat, G. Varas, O. Ramos + A. Mishra, P. Personnettaz, G. Mamatsashvili, V. Galindo, F. Stefani - Estimating Spatially Resolved Radiation Fields Using Neural Networks - https://arxiv.org/abs/2512.17654 - arXiv:2512.17654v1 Announce Type: cross -Abstract: We present an in-depth analysis on how to build and train neural networks to estimate the spatial distribution of scattered radiation fields for radiation protection dosimetry in medical radiation fields, such as those found in Interventional Radiology and Cardiology. Therefore, we present three different synthetically generated datasets with increasing complexity for training, using a Monte-Carlo Simulation application based on Geant4. On those datasets, we evaluate convolutional and fully connected architectures of neural networks to demonstrate which design decisions work well for reconstructing the fluence and spectra distributions over the spatial domain of such radiation fields. All used datasets as well as our training pipeline are published as open source in separate repositories. - oai:arXiv.org:2512.17654v1 - cs.LG - physics.comp-ph - physics.med-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross - http://creativecommons.org/licenses/by-sa/4.0/ - Felix Lehner, Pasquale Lombardo, Susana Castillo, Oliver Hupe, Marcus Magnor + Unified Micromechanics Theory of Composites + https://arxiv.org/abs/2503.14529 + arXiv:2503.14529v2 Announce Type: replace +Abstract: We consider the matrix composite materials (CM) of either random (statistically homogeneous or inhomogeneous), periodic, or deterministic (neither random nor periodic) structures. CMs exhibit linear or nonlinear behavior, coupled or uncoupled multi-physical phenomena, locally elastic, weakly nonlocal (strain gradient and stress gradient), or strongly nonlocal (strain-type and displacement-type, peridynamics) phase properties. A modified Computational Analytical Micromechanics (CAM) approach introduces an exact Additive General Integral Equation (AGIE) for CMs of any structure and phase properties mentioned above. The unified iteration solution of static AGIEs is adapted to the body force with compact support serving as a fundamentally new universal training parameter. The approach also establishes a critical threshold for filtering out unsuitable sub-datasets of effective parameters through a novel Representative Volume Element (RVE) concept, which extends Hill's classical framework. This RVE concept eliminates sample size, boundary layer, and edge effects, making it applicable to CMs of any structure and phase properties, regardless of local or nonlocal, linear or nonlinear. Incorporating this new RVE concept into machine learning and neural network techniques enables the construction of any unpredefined surrogate nonlocal operators. The methodology is structured as a modular, block-based framework, allowing independent development and refinement of software components. This flexible, robust AGIE-CAM framework integrates data-driven, multi-scale, and multi-physics modeling, accelerating research in CM of any microtopology and phase properties considered. The AGIE-CAM framework represents a groundbreaking paradigm shift in the micromechanics of composites, redefining the very philosophy that underpins our understanding of their behavior at the microscopic level. + oai:arXiv.org:2503.14529v2 + physics.class-ph + cond-mat.mtrl-sci + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + Valeriy A. Buryachenko - Networks as the fundamental constituents of the universe - https://arxiv.org/abs/2512.17676 - arXiv:2512.17676v1 Announce Type: cross -Abstract: We review an approach that uses binary relations as the fundamental constituents of the universe, utilizing them as building blocks for both space and matter. The model is defined by an ultraviolet continuous fixed point of a statistical model on random networks, governed by the combinatorial Ollivier-Ricci curvature, which acts as a network analogue of the Einstein-Hilbert action. The model exhibits two distinct phases separated by this fixed point, a geometric and a random phase, representing space and matter, respectively. At weak coupling and on large scales, the network organizes into a holographic surface whose collective state encodes both an emergent 3D space and the matter distributed in it. The Einstein equations emerge as constitutive relations expressing matter in terms of fundamental network degrees of freedom while dynamics in a comoving frame is governed by relativistic quantum mechanics. Quantum mechanics, however is an effective theory breaking down at the scale of the radius of curvature of the holographic network. On smaller scales, not only relativistic invariance is lost but also the Lorentzian signature of space-time. Finally, the manifold nature of space-time breaks down on the Planck length, where the random character of the fundamental network on the smallest scales becomes apparent. The network model seems to naturally encode several of the large-distance features of cosmology, albeit still at a qualitative level. The holographic property of black holes arises intrinsically from the expander nature of random regular graphs. There is a natural mechanism to resolve the cosmological constant problem and dark matter appears naturally as a metastable allotrope in the network fabric of space-time. In this model, both gravity and quantum mechanics are macroscopic statistical effects reflecting the free energy minimization of fundamental binary degrees of freedom. - oai:arXiv.org:2512.17676v1 - gr-qc - cond-mat.stat-mech - hep-th - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Transfer ABCD Matrix for Time-Varying Media and Time Crystals + https://arxiv.org/abs/2503.15063 + arXiv:2503.15063v2 Announce Type: replace +Abstract: This paper introduces a formal definition of the transfer ABCD parameters in time-varying electromagnetic systems. The formal definition comes after the rearrangement of the fields $D$ and $B$ at the inputs and outputs of the temporal system based on the time-varying boundary conditions. Then, we derive the ABCD parameters of a temporal transmission line, i.e., a temporal slab, and compute the associated scattering parameters (reflection and transmission coefficients). The results presented here open up an alternative way, based on network theory, to analyze multilayer temporal configurations. Moreover, we show that the ABCD parameters can be used to compute the dispersion diagram ($\omega$ vs $k$) of time crystals. + oai:arXiv.org:2503.15063v2 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1109/TAP.2025.3602115 + IEEE Transactions on Antennas and Propagation, vol. 73, no. 12, pp. 10931-10936, 2025 + Carlos Molero, Pablo H. Zapata-Cano, Antonio Alex-Amor + + + In situ axion generation and detection in laser-plasma wakefield interaction + https://arxiv.org/abs/2504.12500 + arXiv:2504.12500v2 Announce Type: replace +Abstract: We propose a laser-plasma wakefield interaction based scheme for in situ axion generation and detection through the Primakoff process. + Strong electromagnetic fields ($\gtrsim 10^{11}$\,V/m) in the wakefield can enhance axion production rates by 2 orders of magnitude compared to conventional light-shining-through-a-wall experiments. By replacing the axion generation stage with laser-wakefield interaction, the axion-photon coupling constraints can achieve the level of $\gagg \sim 10^{-10}\,\text{GeV}^{-1}$ for axion mass less than 0.1\,meV. + Besides, the generated axions can convert back into photons in the background fields, leading to axion-regenerated electromagnetic fields (AREM) with unique polarization, frequency, and transverse modes. + This provides a new promising way to search axions by detecting the filtered AREM fields from the background laser and plasma fields. + oai:arXiv.org:2504.12500v2 + physics.plasm-ph + hep-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - J. Phys. Complex. 6 (2025) 042001 - Carlo A. Trugenberger + Xiangyan An, Min Chen, Jianglai Liu, Zhan Bai, Liangliang Ji, Zhengming Sheng, Jie Zhang - Internal Waves Control Bulk Flow in Silos - https://arxiv.org/abs/2512.17686 - arXiv:2512.17686v1 Announce Type: cross -Abstract: We experimentally measure paticle acceleration within the bulk during the discharge of a granular silo. We highlight the existence of a deceleration wave emerging at the outlet level near the dead zone and propagates toward the top of the medium. The wave emission frequency is extracted from spatiotemporal diagrams of the Eulerian instantaneous acceleration profiles. Surprisingly, we find that this frequency decreases with the cohesion of the medium and is independent of the outlet size. - oai:arXiv.org:2512.17686v1 + Separating water content from network dynamics in cell nuclei with Brillouin microscopy + https://arxiv.org/abs/2504.17362 + arXiv:2504.17362v2 Announce Type: replace +Abstract: Probing forces, deformations and generally speaking the mechanical properties of cells is the hallmark of mechanobiology. In the last two decades many techniques have been developed to this end that are largely based on deforming the cells and measuring the reaction force. In cells, an alternative approach has been implemented mid 2010's, based on Brillouin Light Scattering (BLS) that produces a spectrum that can be interpreted as the response of the sample to an infinitesimal uniaxial compression at picosecond timescales. In all of these measurements, the response of the cell is quantified with a colloquial "stiffness" that encompasses both the contribution of load-bearing structures and volume changes, much to confusion. To clarify the interpretation of the hypersonic data obtained from BLS spectra, we vary the relative volume fraction of intracellular water and solid network by applying osmotic compressions to single cells. In the nucleus, we observe a non-linear increase in the sound velocity and attenuation with increasing osmotic pressure that we fit to a poroelastic model, providing an estimate of the friction coefficient between the water phase and the network. By comparing BLS data to volume measurements, our approach demonstrates clearly that BLS shift alone is mostly sensitive to water content while the additional analysis of the linewidth allows identifying the contribution of the biopolymer-based network dynamics in living cells. + oai:arXiv.org:2504.17362v2 + physics.bio-ph cond-mat.soft + q-bio.QM + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Lucie Vovard, Alexis Viel, Estelle Bastien, Lou-Anne Goutier, Gaetan Jardine, Jeremie Margueritat, Sylvain Monnier, Thomas Dehoux + + + Experimental Study On Flashing-Induced Instabilities In An Open Natural Circulation System + https://arxiv.org/abs/2506.06213 + arXiv:2506.06213v2 Announce Type: replace +Abstract: The natural circulation system (NCS) uses gravity pressure drop caused by density differences in the loop to generate the driving force without any external mechanical devices, which has been widely applied to the design of the nuclear reactor system and the passive safety system due to its simple structure, high intrinsic safety, and strong heat discharge capacity. However, the low-pressure condition can lead to a two-phase flow and make the flow characteristics in the NCS more complex. Flashing-induced instability occurring in the open NCS will cause the system structural vibration as well as mechanical damage and bring safety problems. The study on flashing-flow behaviors in an open NPS has been conducted experimentally in this paper. High-speed camera, thermal needle probe and wire-mesh sensor were adopted to record the flow pattern and measure the void fraction in the polycarbonate visualization riser section. In the start-up process, with the inlet temperature in the riser section increasing, the open NCS has experienced single-phase stable flow, intermittent oscillation between single-phase and two-phase, high subcooling two-phase stable flow, flashing-induced instabilities flow, and low subcooling two-phase stable flow. The flow pattern evolution of flow flashing goes through bubble flow, cap-slug flow, churn flow and wispy annular flow, in which the length of churn can account for more than 40% length of the two-phase regime. The flash number Nflash is used to divide the region of flashing-induced instabilities. It is found that the open NCS is in a stable two-phase flow when the flash number at the outlet of the riser section N_{flash,out} = 4\sim 5. + oai:arXiv.org:2506.06213v2 physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - David Luce, Adrien Gans, Nicolas Vandewalle, S\'ebastien Kiesgen de Richter + Yuliang Fang, Xiaxin Cao, Wenxi Tian - Revisiting the Broken Symmetry Phase of Solid Hydrogen: A Neural Network Variational Monte Carlo Study - https://arxiv.org/abs/2512.17703 - arXiv:2512.17703v1 Announce Type: cross -Abstract: The crystal structure of high-pressure solid hydrogen remains a fundamental open problem. Although the research frontier has mostly shifted toward ultra-high pressure phases above 400 GPa, we show that even the broken symmetry phase observed around 130~GPa requires revisiting due to its intricate coupling of electronic and nuclear degrees of freedom. Here, we develop a first principle quantum Monte Carlo framework based on a deep neural network wave function that treats both electrons and nuclei quantum mechanically within the constant pressure ensemble. Our calculations reveal an unreported ground-state structure candidate for the broken symmetry phase with $Cmcm$ space group symmetry, and we test its stability up to 96 atoms. The predicted structure quantitatively matches the experimental equation of state and X-ray diffraction patterns. Furthermore, our group-theoretical analysis shows that the $Cmcm$ structure is compatible with existing Raman and infrared spectroscopic data. Crucially, static density functional theory calculation reveals the $Cmcm$ structure as a dynamically unstable saddle point on the Born-Oppenheimer potential energy surface, demonstrating that a full quantum many-body treatment of the problem is necessary. These results shed new light on the phase diagram of high-pressure hydrogen and call for further experimental verifications. - oai:arXiv.org:2512.17703v1 - cond-mat.str-el - cond-mat.mtrl-sci - cs.LG - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Magnetically tunable singularity of Moire bound states in the continuum + https://arxiv.org/abs/2506.16828 + arXiv:2506.16828v3 Announce Type: replace +Abstract: We investigate the band structure and the dynamics of topological singularities of magneto-optical Moir\'e bound states in the continuum (BICs), which originate from two overlapped conventional magneto-optical BIC gratings with mismatched periods. We show that breaking time-reversal symmetry by applying an external magnetic field in different directions can effectively manipulate the Moir\'e BICs' topological singularities, which exhibit a high Q factor throughout the momentum space. + oai:arXiv.org:2506.16828v3 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Shengdu Chai, Chen Lin, Xinyang Dong, Yuqiang Li, Wanli Ouyang, Lei Wang, X. C. Xie + Shuo Wang - Corrosion-resistant and conductive Ti-Nb-O coatings tailored for ultra-low Pt-loaded BPPs and PTLs in PEM electrolyzers - https://arxiv.org/abs/2512.17721 - arXiv:2512.17721v1 Announce Type: cross -Abstract: We develop highly corrosion-resistant and conductive Ti-Nb-O coatings for metallic components -- bipolar plates (BPPs) and porous transport layers (PTLs) -- in PEM water electrolyzers. Using reactive high-power impulse magnetron sputtering (HiPIMS), we deposit compact 200 nm bilayer coatings onto SS316L substrates, systematically tailoring their composition. By precisely controlling oxygen partial pressure and Nb/Ti ratio, we adjust stoichiometry and structure, directly affecting electrical resistivity and corrosion resistance. We examine interfacial contact resistance (ICR) and electrochemical parameters before and after accelerated corrosion testing. Optimized coatings exhibit resistivity on the order of 10^-4 Ohmcm and extremely low corrosion current densities (J_corr = 0.01-0.08 uA/cm^2), well below the U.S. DOE 2026 target. Most importantly, these coatings enable the ICR target after accelerated corrosion testing with a Pt overlayer as thin as 5 nm, reducing Pt loading by up to two orders of magnitude compared to conventional approaches. - oai:arXiv.org:2512.17721v1 - cond-mat.mtrl-sci + Full-spectrum modeling of mobile gamma-ray spectrometry systems in scattering media + https://arxiv.org/abs/2506.17820 + arXiv:2506.17820v2 Announce Type: replace +Abstract: Mobile gamma-ray spectrometry (MGRS) systems are essential for localizing, identifying, and quantifying gamma-ray sources in complex environments. Full-spectrum template matching offers the highest accuracy and sensitivity for these tasks but is limited by the computational cost of generating the required spectral templates. Here, we present a generalized full-spectrum modeling framework for MGRS systems in scattering media, enabling near-real-time template generation through dynamic, anisotropic instrument response functions. Benchmarked against high-fidelity brute-force Monte Carlo simulations, our method yields a computational speedup by a factor of $\mathcal{O}(10^7)$, while achieving comparable accuracy with median spectral deviations below 6%. The methodology presented is platform-agnostic and applicable across marine, terrestrial, and airborne domains, unlocking new capabilities for MGRS in a variety of applications, such as environmental monitoring, geophysical exploration, nuclear safeguards, and radiological emergency response. + oai:arXiv.org:2506.17820v2 + physics.ins-det physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + physics.comp-ph + physics.geo-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - David Kolenat\'y, Ji\v{r}\'i \v{C}apek, Stanislav Haviar, Ji\v{r}\'i Rezek, Radom\'ir \v{C}erstv\'y, Akash Kumar, Kalyani Shaji, Mariia Zhadko, Petr Zeman + David Breitenmoser, Alberto Stabilini, Malgorzata Magdalena Kasprzak, Sabine Mayer - Condensation dynamics of sticky and anchored flexible biopolymers - https://arxiv.org/abs/2512.17745 - arXiv:2512.17745v1 Announce Type: cross -Abstract: Cells regulate gene expression in part by forming DNA-protein condensates in the nucleus. While existing theories describe the equilibrium size and stability of such condensates, their dynamics remain less understood. Here, we use coarse-grained 3D Brownian-dynamics simulations to study how long, end-anchored biopolymers condense over time due to transient crosslinking. By tracking how clusters nucleate, merge, and disappear, we identify two dominant dynamical pathways, ripening and merging, that govern the progression from an uncompacted chain to a single condensate. We show how microscopic kinetic parameters, protein density, and mechanical constraints shape these pathways. Using insights from the simulations, we construct a minimal mechanistic free-energy model that captures the observed scaling behavior. Together, these results clarify the dynamical determinants of DNA and chromatin reorganization on timescales relevant to gene regulation. - oai:arXiv.org:2512.17745v1 - cond-mat.soft - physics.bio-ph + IRENE: a fluId layeR finitE-elemeNt softwarE + https://arxiv.org/abs/2506.17827 + arXiv:2506.17827v3 Announce Type: replace +Abstract: We present a finite-element software library, IRENE, which allows to solve numerically the dynamics of a viscous fluid layer embedded in three-dimensional space. Unlike finite-element libraries present in the literature, IRENE can handle two-dimensional open surfaces with a wide range of boundary conditions, and inter-surface obstacles with any shapes, and is built upon the user-friendly and versatile finite element computational software (FEniCS). Also, the library can describe a wide range of physical regimes--both low-Reynolds-number and inertia-dominated ones--capturing the complex coupling between in-plane flows, out-of-plane deformations, surface tension, and elastic response. We validate IRENE against known analytical and numerical results, and demonstrate its capabilities through physical examples. Overall, IRENE provides a versatile and efficient tool for understanding fluid-layer dynamics on multiple physical scales, from flows of lipidic membranes on a microscopic level, to fluid flows on a macroscopic scale, to atmospheric air flows on a planetary level. + oai:arXiv.org:2506.17827v3 + physics.flu-dyn physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - Adam R. Lamson, Mohammadhossein Firouznia, Michael J. Shelley + Dennis W\"orthm\"uller, Gaetano Ferraro, Pierre Sens, Michele Castellana - Mechanistic Origin of Charge Separation and Enhanced Photocatalytic Activity in D-$\pi$-A-Functionalized UiO-66-NH$_2$ MOFs - https://arxiv.org/abs/2512.17778 - arXiv:2512.17778v1 Announce Type: cross -Abstract: Donor-$\pi$-acceptor (D-$\pi$-A) functionalization of MOF linkers can enhance visible-light photocatalytic activity, yet the mechanisms responsible for these effects remain unclear. Here we combine EPR spectroscopy, transient photoluminescence, and first-principles calculations to examine how diazo-coupled anisole, diphenylamine (DPA), and N,N-dimethylaniline (NNDMA) groups modify the photophysics of UiO-66-NH$_2$. All donor units introduce new occupied states near the valence-band edge, enabling charge separation through dye-to-framework electron transfer. Among them, the anisole-modified material stands out for facilitating efficient intersystem crossing into a triplet charge-transfer configuration that suppresses fast recombination and yields long-lived charge carriers detectable by photo-EPR. Meanwhile, bulkier donors such as DPA and NNDMA - despite their stronger electron-donating character - also tend to introduce defect-associated trap states. These results underscore the interplay between donor-induced electronic-structure changes, triplet pathways, and defect-mediated recombination, offering a mechanistic basis for tuning photocatalytic response in D-$\pi$-A-modified MOFs. - oai:arXiv.org:2512.17778v1 - cond-mat.mtrl-sci - physics.app-ph - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Chiral superfluorescence from perovskite superlattices + https://arxiv.org/abs/2506.22786 + arXiv:2506.22786v2 Announce Type: replace +Abstract: Superfluorescence (SF) is the collective emission of intense, coherent light from an interacting ensemble of quantum emitters1-4. While SF has been observed in several solid-state materials5-8, the spontaneous generation of circularly polarized SF from chiral materials (chiral SF) has not been realized9,10. Here, we report the first observation of chiral SF originating from edge states in large-area (>100 um * 100 um) vertically aligned chiral perovskite superlattices at room-temperature. Theoretical quantum optics calculations describe the transition from initially unpolarized, incoherent spontaneous emission to a coherent chiral SF state, quantitatively reproducing both the experimentally observed generation of circular polarization (up to ~14%) and its reversal in sign with opposite material handedness. Moreover, we show that both the intensity and the degree of circular polarization of chiral SF can be modulated by a weak magnetic field, enabling precise control over solid-state quantum light emission at room temperature. Our findings demonstrate an interplay between chirality and many-body quantum coherence, thereby revealing promising new directions for chirality-controlled quantum-optical applications. + oai:arXiv.org:2506.22786v2 + physics.optics + cond-mat.mes-hall + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Anastasiia Kultaeva, Volodymyr Vasylkovskyi, Andreas Sperlich, Eugenio Otal, Katsuya Teshima, Wolf Gero Schmidt, Timur Biktagirov + Qi Wei, Jonah S. Peter, Hui Ren, Weizhen Wang, Luwei Zhou, Qi Liu, Stefan Ostermann, Jun Yin, Songhua Cai, Susanne F. Yelin, Mingjie Li - Systematic search of laser and phase modulation noise coupling in heterodyne interferometry - https://arxiv.org/abs/2512.17802 - arXiv:2512.17802v1 Announce Type: cross -Abstract: Heterodyne interferometry for precision science often comes with an optical phase modulation, for example, for intersatellite clock noise transfer for gravitational wave (GW) detectors in space, exemplified by the Laser Interferometer Space Antenna (LISA). The phase modulation potentially causes various noise couplings to the final phase extraction of heterodyne beatnotes by a phasemeter. In this paper, in the format of space-based GW detectors, we establish an analytical framework to systematically search for the coupling of various noises from the heterodyne and modulation frequency bands, which are relatively unexplored so far. In addition to the noise caused by the phase modulation, the high-frequency laser phase noise is also discussed in the same framework. The analytical result is also compared with a numerical experiment to confirm that our framework successfully captures the major noise couplings. We also demonstrate a use case of this study by taking the LISA-like parameters as an example, which enables us to derive requirements on the level of the laser and phase modulation noises in the high frequency regimes. - oai:arXiv.org:2512.17802v1 - astro-ph.IM - physics.app-ph + Polarization and tranverse mode nonlinear dynamics in a multimode VCSEL + https://arxiv.org/abs/2507.01186 + arXiv:2507.01186v2 Announce Type: replace +Abstract: We theoretically analyze the nonlinear dynamics and routes to chaos in a multimode vertical cavity surface-emitting laser (MM-VCSEL) in free-running operation. Including higher order transverse modes (TMs) results in additional bifurcations at higher currents not found for single-mode VCSELs (SM-VCSELs). The resulting dynamics involve competition between modes with different transverse profiles and polarization and show good qualitative agreement with recent experiments. + oai:arXiv.org:2507.01186v2 physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 - cross + nlin.CD + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1364/OL.572473 + Opt. Lett. 50, 7645 (2025) + Yohann G. Sanvert, Jules Mercadier, Stefan Bittner, Angel Valle, Marc Sciamanna + + + Quantum Listenings -- Amateur Sonification of Vacuum and other Noises + https://arxiv.org/abs/2507.08813 + arXiv:2507.08813v2 Announce Type: replace +Abstract: The sensory perceptions of vision and sound may be considered as complementary doorways towards interpreting and understanding physical phenomena. We provide a few selected samples where scientific data of systems usually not directly accessible to humans may be listened to. The examples are chosen close to the regime where quantum mechanics is applicable. Visual and auditory renderings are compared with some connections to music, illustrating in particular a kind of fractal complexity along the time axis. + oai:arXiv.org:2507.08813v2 + physics.pop-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Carsten Henkel + + + Terahertz Wave Generation in Two-Dimensional MXenes under Femtosecond Pulsed Laser Illumination + https://arxiv.org/abs/2507.11656 + arXiv:2507.11656v2 Announce Type: replace +Abstract: The efficient generation of terahertz (THz) waves in two-dimensional (2D) MXene layers driven by near-infrared femtosecond laser pulses is demonstrated through predictive simulations. Employing a novel hydrodynamic model that self-consistently captures nonlinearities from electric, magnetic, and convective interactions with a minimal set of material parameters. The coupled hydrodynamic-Maxwell equations are solved via finite-difference time-domain (FDTD) methods to resolve the spatiotemporal dynamics of laser-induced carriers and THz emission. The results reveal strong, tunable THz output dependent on laser (intensity, polarization, incidence angle), material (composition, carrier density, temperature), and struc-tural (layer thickness, substrate) parameters. These predictions offer verifiable guidelines for experiments and position MXenes as versatile platforms for compact, broadband THz sources in on-chip photonics and 6G communications. This work establishes a robust, self-contained framework for modeling ultrafast nonlinear optics in 2D materials. + oai:arXiv.org:2507.11656v2 + physics.optics + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + A. A. Molavi Choobini, A. Chimeh + + + Physics-Informed Regression Modelling for Vertical Facade Surface Temperature: A Tropical Case Study on Solar-reflective Material + https://arxiv.org/abs/2507.16174 + arXiv:2507.16174v2 Announce Type: replace +Abstract: Urban heat islands (UHIs) pose a critical challenge in densely populated cities and tropical climates where large amounts of energy are used to meet the cooling demand. To address this, Building and Construction Authority (BCA) of Singapore provides incentives for passive cooling such as using of solar-reflective material in its Green Mark guidelines. Thus, understanding about its real-world effectiveness in tropical urban environments is required. This study evaluated the effectiveness of solar-reflective cool paint using a hybrid modelling framework combining a transient physical model and data driven model through field measurements. Several machine learning algorithms were compared including multiple-linear regression (MLR), random forest regressor (RF), AdaBoost regressor (AB), extreme gradient boosting regressor (XGB), and TabPFN regressor (TPR). The results indicated that the transient physical model overestimated facade temperatures in the lower temperature ranges. The physics-informed MLR achieved best performance with improved accuracy for pre-cool paint (R2=0.96, RMSE=0.83C) and post-cool paint (R2=0.95, RMSE=0.65C) scenarios, reducing RMSE by 26% and 44%, respectively. The hybrid model also effectively predicted hourly heat fluxes revealing substantial reductions in surface temperature and heat storage with increasing albedo. The maximum net heat flux q_net was reduced by about 30-65 W/m2 in the post-cool paint stage (albedo = 0.73) compared to the pre-cool paint stage (albedo = 0.31). As albedo increases from 0.1 to 0.9, the sensitivity analysis predicts that the maximum daytime surface temperature will decrease by about 11C and the peak heat release of the net heat flux will decrease significantly from about 161 W/m2 to 27 W/m2. + oai:arXiv.org:2507.16174v2 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Shisheng Chen, Shanshan Tong, Nyuk Hien Wong, May Lwin Oo, Joie Lim, Erna Tan, Ruohan Xu, Marcel Ignatius, Yang He + + + FFTArray: A Python Library for the Implementation of Discretized Multi-Dimensional Fourier Transforms + https://arxiv.org/abs/2508.03697 + arXiv:2508.03697v3 Announce Type: replace +Abstract: Partial differential equations describing the dynamics of physical systems rarely have closed-form solutions. Fourier spectral methods, which use Fast Fourier Transforms (FFTs) to approximate solutions, are a common approach to solving these equations. However, mapping Fourier integrals to discrete FFTs is not straightforward, as the selection of the grid as well as the coordinate-dependent phase and scaling factors require special care. Moreover, most software packages that deal with this step integrate it tightly into their full-stack implementations. Such an integrated design sacrifices generality, making it difficult to adapt to new coordinate systems, boundary conditions, or problem-specific requirements. To address these challenges, we present FFTArray, a Python library that automates the general discretization of Fourier transforms. Its purpose is to reduce the barriers to developing high-performance, maintainable code for pseudo-spectral Fourier methods. Its interface enables the direct translation of textbook equations and complex research problems into code, and its modular design scales naturally to multiple dimensions. This makes the definition of valid coordinate grids straightforward, while coordinate grid specific corrections are applied with minimal impact on computational performance. Built on the Python Array API Standard, FFTArray integrates seamlessly with array backends like NumPy, JAX and PyTorch and supports Graphics Processing Unit acceleration. The code is openly available at https://github.com/QSTheory/fftarray under Apache-2.0 license. + oai:arXiv.org:2508.03697v3 + physics.comp-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - Kohei Yamamoto, Olaf Hartwig, Lennart Wissel, Holly Leopardi, Kenji Numata, Ryan Derosa + Stefan J. Seckmeyer, Christian Struckmann, Gabriel M\"uller, Jan-Niclas Kirsten-Siem{\ss}, Naceur Gaaloul - Active learning emulators for nuclear two-body scattering in momentum space - https://arxiv.org/abs/2512.17842 - arXiv:2512.17842v1 Announce Type: cross -Abstract: We extend the active learning emulators for two-body scattering in coordinate space with error estimation, recently developed by Maldonado et al. in Phys. Rev. C \textbf{112}, 024002, to coupled-channel scattering in momentum space. Our full-order model (FOM) solver is based on the Lippmann-Schwinger integral equation for the scattering $t$-matrix as opposed to the radial Schr\"odinger equation. We use (Petrov-)Galerkin projections and high-fidelity calculations at a few snapshots across the parameter space of the interaction to construct efficient reduced-order models (ROMs), trained by a greedy algorithm for locally optimal snapshot selection. Both the FOM solver and the corresponding ROMs are implemented efficiently in Python using Google's JAX library. We present results for emulating scattering phase shifts in coupled and uncoupled channels and cross sections, and assess the accuracy of the developed ROMs and their computational speed-up factors. We also develop emulator error estimation for both the $t$-matrix and the total cross section. The software framework for reproducing and extending our results will be made publicly available. Together with our recent advances in developing active-learning emulators for three-body scattering, these emulator frameworks set the stage for full Bayesian calibrations of chiral nuclear interactions and optical models against scattering data with quantified emulator errors. - oai:arXiv.org:2512.17842v1 - nucl-th - hep-ph - nucl-ex - physics.data-an - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Finite-time gradient blow-up and shock formation in Israel-Stewart theory: Bulk, shear, and diffusion regimes + https://arxiv.org/abs/2508.04717 + arXiv:2508.04717v2 Announce Type: replace +Abstract: We present the first demonstration of finite-time gradient blow-ups in Israel-Stewart (IS) theories with 1+1D plane symmetry, mathematically showing the existence of smooth initial data that can evolve into shocks across three regimes: pure bulk viscosity, shear viscosity, and diffusion. Through numerical simulations of bulk-viscous fluids, we verify that these shocks satisfy Rankine-Hugoniot conditions, exhibit characteristic velocity crossing (Mach number obeys $\mathcal{M}_u > 1 > \mathcal{M}_d$), and maintain thermodynamic consistency, required for physical shocks. Our results reveal a crucial early-time dynamical phase -- previously unexplored in steady-state analyses -- where nonlinear effects dominate viscous damping, resolving the apparent impossibility of IS-type theories predicting shock formation. While restricted to simplified 1+1D systems with separate viscous effects, this work establishes foundational insights for shock formation in relativistic viscous hydrodynamics, highlighting critical challenges for extending to 3+1D systems or to a full IS theory where multiple nonlinear modes interact. The findings emphasize that both initial data structure and numerical methodology require careful consideration when studying shocks in relativistic viscous fluids. + oai:arXiv.org:2508.04717v2 + physics.gen-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - A. Giri, J. Kim, C. Drischler, Ch. Elster, R. J. Furnstahl + 10.1103/blhw-xplr + Phys. Rev. E 112 (2025) 065105 + F\'abio S. Bemfica - Witnessing Entanglement in Mixed-Particle Quantum Systems - https://arxiv.org/abs/2512.17860 - arXiv:2512.17860v1 Announce Type: cross -Abstract: We introduce an entanglement witness that identifies off-diagonal long-range order (ODLRO) -- a distinctive form of entanglement -- in systems containing both fermionic and bosonic particles. By analyzing the particle-hole reduced density matrices of each subsystem, the approach detects ODLRO independently in both fermionic and bosonic sectors and identifies when long-range order develops across the entire mixed-particle system. The witness also quantifies the magnitude of ODLRO within each particle type, revealing how fermionic and bosonic correlations combine to form the total entanglement of the system, including a bosonic condensation of particle-hole pairs driven by many-body correlations rather than particle statistics. Using the Lipkin-Meshkov-Glick spin model, we show how the transition from ODLRO localized to one particle type to ODLRO shared by both particle types captures the onset of collective entanglement in a mixed-particle environment, providing new insight into systems where fermionic and bosonic correlations coexist. - oai:arXiv.org:2512.17860v1 + Near-optimal decomposition of unitary matrices using phase masks and the discrete Fourier transform + https://arxiv.org/abs/2508.20010 + arXiv:2508.20010v2 Announce Type: replace +Abstract: Universal multiport interferometers (UMIs) have emerged as a key tool for performing arbitrary linear transformations on optical modes, enabling precise control over the state of light in essential applications of classical and quantum information processing such as neural networks and boson sampling. While UMI architectures based on Mach-Zehnder interferometer networks are well established, alternative approaches that involve interleaving fixed multichannel mixing layers and phase masks have recently gained interest due to their high robustness to losses and fabrication errors. However, these approaches currently lack optimal analytical methods to compute design parameters with low optical depth. In this work, we introduce a constructive decomposition of unitary matrices using a sequence of $2N+5$ phase masks interleaved with $2N+4$ discrete Fourier transform matrices. This decomposition can be leveraged to design universal interferometers based on phase masks and multimode interference couplers, implementing a discrete Fourier transform, offering an analytical alternative to conventional numerical optimization-based designs and reducing by a factor of 3 the previous best known analytical methods. + oai:arXiv.org:2508.20010v2 + physics.optics quant-ph - physics.chem-ph - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Irma Avdic, David A. Mazziotti + 10.1364/JOSAB.577579 + Journal of the Optical Society of America B Vol. 43, Issue 3, pp. A66-A73 (2026) + Vincent Girouard, Nicol\'as Quesada - Experimentally Mapping the Phase Diagrams of Photoexcited Small Polarons - https://arxiv.org/abs/2512.17869 - arXiv:2512.17869v1 Announce Type: cross -Abstract: Understanding the fundamental properties that dictate photoexcited polarons in materials is critical to tuning their properties. Theoretical models of polarons have only recently been extended to the excited state. Experimental measurements of polaron formation and transport have been widely undertaken across a range of materials, from photocatalysts and superconductors to soft conducting polymers. Here, we map experimental measurements of quantities such as polaron strength onto phase diagrams of the Holstein, Hubbard-Holstein, and t-J-Holstein models. This work demonstrates that tuning electron-phonon coupling strength, electron localization, and spin exchange can be leveraged to suppress or control polaron formation in transition metal oxides. We find that the t-J-Holstein model best describes the measured iron oxides and could be generally applied to a wide range of systems that exhibit polaron formation in the excited state. This work combines experimental data with ground state models to provide a robust parameter space for informing photoexcited polaron design. - oai:arXiv.org:2512.17869v1 - cond-mat.mtrl-sci - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross + Classical and quantum beam dynamics simulation of the RF photoinjector test bench + https://arxiv.org/abs/2509.00732 + arXiv:2509.00732v3 Announce Type: replace +Abstract: We present beam-dynamics simulations for an S-band RF photoinjector test bench under development at the Joint Institute for Nuclear Research. The facility is intended to produce high-quality electron beams and to enable future generation of relativistic vortex electrons carrying quantized orbital angular momentum (OAM). Simulations of a 1.5-cell RF photogun operating at the currently available accelerating gradient of 45 MV/m demonstrate stable bunch formation at low bunch charge (Q = 0.63 pC), where space-charge effects are weak and the transverse emittance is primarily determined by RF-induced correlations. Optimization of the injection phase and the cathode-region solenoid field results in a robust emittance-compensated regime, yielding a final normalized emittance of 3.2 pi mm mrad. To evaluate the prospects for accelerating vortex electron beams, we further model the quantum evolution of single-electron Laguerre-Gaussian wave packets. The simulations show that acceleration to the multi-MeV energy range significantly suppresses free-space wave-packet spreading and preserves the initial OAM structure, indicating that the proposed test bench provides suitable conditions for forthcoming experimental studies of relativistic vortex electrons. + oai:arXiv.org:2509.00732v3 + physics.acc-ph + physics.atom-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace http://creativecommons.org/licenses/by/4.0/ - Jocelyn L. Mendes, Scott K. Cushing + A. S. Dyatlov, A. V. Afanasyev, V. V. Kobets, A. E. Levichev, M. V. Maksimov, D. A. Nikiforov, M. A. Nozdrin, K. Popov, K. A. Sibiryakova, K. E. Yunenko, D. V. Karlovets - Simulation of topological superconductors and their competing orders using photon-mediated interactions - https://arxiv.org/abs/2512.17889 - arXiv:2512.17889v1 Announce Type: cross -Abstract: Realizing and controlling the unconventional pairing featured by topological superconductors remains a central challenge. We introduce a cavity QED quantum simulator that engineers competing chiral $p_x+ip_y$ and $d_{x^2-y^2}+id_{xy}$ orders by tailoring cavity-mediated couplings between atomic pseudospins that emulate momentum-dependent pairing channels. The desired spatially inhomogeneous cavity-mediated couplings can be engineered in a 2D optical lattice using incommensurate cavity-lattice wavelengths naturally occurring in cavity QED systems. This minimal and fully tunable platform enables controlled state preparation and continuous measurement of superconducting order parameters, revealing phases in both equilibrium and sudden-quench settings with a single dominant pairing channel, as well as coexistence regimes with competing pairing channels. Crucially, our implementation allows direct observation of topological transitions in and out of equilibrium, providing a powerful route to the quantum simulation of competing topological superconducting phases that remain elusive in solid-state and ultracold-atom systems. - oai:arXiv.org:2512.17889v1 - quant-ph - cond-mat.quant-gas - physics.atom-ph - Mon, 22 Dec 2025 00:00:00 -0500 - cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Anjun Chu, Joyce Kwan, Eric Yilun Song, Seth Hew Peng Chew, James K. Thompson, Ana Maria Rey + Inflection point instability in Hartmann channel flow with variable electric conductivity + https://arxiv.org/abs/2509.02086 + arXiv:2509.02086v2 Announce Type: replace +Abstract: The stability of a flow of an electrically conducting, incompressible fluid in a channel with an imposed uniform wall-normal magnetic field and electrically insulating walls is studied using linear stability analysis and direct numerical simulations. The novelty of the system, which differentiates it from the classical Hartmann channel flow, is that, as in some technological applications of liquid metals, the electric conductivity and viscosity of the fluid vary across the channel. This variation is found to have a strong influence on the stability characteristics of the flow. Specifically, a linear variation in electric conductivity significantly alters the base velocity profile, leading to pronounced asymmetry and the development of inflection points. When this transformation is sufficiently strong, the flow becomes linearly unstable at Reynolds numbers much lower than the threshold for the linear instability of the Hartmann channel flow. The instability exhibits distinct features: a large typical axial wavelength and the localization of perturbation growth in the channel core. The characteristics of this instability suggest a mechanism similar to the classical inviscid inflection-point instability of one-dimensional velocity profiles. The resulting transition to turbulence is demonstrated in direct numerical simulations. + oai:arXiv.org:2509.02086v2 + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + Roman Okatev, Oleg Zikanov, Dmitry Krasnov, Peter Frick - Multivariate Joint Recurrence Quantification Analysis: detecting coupling between time series of different dimensionalities - https://arxiv.org/abs/2303.16907 - arXiv:2303.16907v2 Announce Type: replace -Abstract: One challenge with the analysis of complex systems and the interaction between such systems is that they are composed of different numbers of components, or simply the fact that a different number of observables is available for each system. The challenge is how to analyze the interaction of two systems which are not described by the same number of variables. Here, we present multivariate joint recurrence quantification analysis (MvJRQA), a recurrence-based technique that allows to analyze coupling properties between multivariate datasets that differ in dimensionality (i.e., number of observables) and type of data (such as nominal or interval-scaled, for example). First, we introduce the methods, and test it on simulated data from linear and nonlinear systems. Then we apply it to an empirical dataset of EEG and eye tracking data. We introduce the joint recurrence coupling indicator (JRCI) as a measure to assess and compare coupling between systems. Finally, we discuss practical issues regarding the application of the method. - oai:arXiv.org:2303.16907v2 - physics.data-an - nlin.CD - Mon, 22 Dec 2025 00:00:00 -0500 + A data-driven method to estimate contamination from light ion beam transmutation at colliders + https://arxiv.org/abs/2509.09736 + arXiv:2509.09736v2 Announce Type: replace +Abstract: Collisions of relativistic light ions such as oxygen, neon, and magnesium, have been proposed as a way to examine the system-size dependence of dynamics typically associated with the quark-gluon plasma produced in collisions of heavier ions such as xenon, gold, or lead. Recent efforts at both the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) have produced large datasets of proton-oxygen, oxygen-oxygen, and neon-neon collisions, catalyzing intense interest in experimental backgrounds associated with light ion collisions. In particular, electromagnetic dissociation of light ions while they are circulating in a collider can result in beam contamination that is difficult to simulate precisely. Here we propose a data-driven method for evaluating the potential impact of beam contaminants on physics analyses. The method exploits the time-dependence and smaller size of contaminant ion species to define control regions that can be used to quantify potential contamination effects. A simple model is used to illustrate the method and to study its robustness. This method can inform studies of recent LHC and RHIC data and could also be useful for future light ion programs at the LHC and beyond. + oai:arXiv.org:2509.09736v2 + physics.acc-ph + nucl-ex + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Sebastian Wallot, Dan M{\o}nster + http://creativecommons.org/licenses/by/4.0/ + Sruthy Jyothi Das, Austin Baty - An AI-driven Assessment of Bone Density as a Biomarker Leading to the Aging Law - https://arxiv.org/abs/2308.02815 - arXiv:2308.02815v2 Announce Type: replace -Abstract: As global population aging intensifies, there is growing interest in the study of biological age. Bones have long been used to evaluate biological age, and the decline in bone density with age is a well-recognized phenomenon in adults. However, the pattern of this decline remains controversial, making it difficult to serve as a reliable indicator of the aging process. Here we present a novel AI-driven statistical method to assess the bone density, and a discovery that the bone mass distribution in trabecular bone of vertebrae follows a non-Gaussian, unimodal, and skewed distribution in CT images. The statistical mode of the distribution is defined as the measure of bone mass, which is a groundbreaking assessment of bone density, named Trabecular Bone Density (TBD). The dataset of CT images are collected from 1,719 patients who underwent PET/CT scans in three hospitals, in which a subset of the dataset is used for AI model training and generalization. Based upon the cases, we demonstrate that the pattern of bone density declining with aging exhibits a consistent trend of exponential decline across sexes and age groups using TBD assessment. The developed AI-driven statistical method blazes a trail in the field of AI for reliable quantitative computation and AI for medicine. The findings suggest that human aging is a gradual process, with the rate of decline slowing progressively over time, which will provide a valuable basis for scientific prediction of life expectancy. - oai:arXiv.org:2308.02815v2 - physics.med-ph - cs.AI - cs.CV - Mon, 22 Dec 2025 00:00:00 -0500 + Electron Inertia and Magnetic Reconnection + https://arxiv.org/abs/2509.14400 + arXiv:2509.14400v3 Announce Type: replace +Abstract: When electron inertia is the only non-ideal effect in the evolution of a magnetic field $\vec{B}$, the field lines of $\vec{B}$ reconnect, but the lines of a related field $\vec{\mathcal{B}}$ do not. $\vec{\mathcal{B}} \equiv \vec{B} + \vec{\nabla}\times \left( (c/\omega_{pe})^2\mu_0\vec{j} \right)$ with $\omega_{pe}$ the plasma frequency and $\vec{j}$ the current density. The non-reconnecting evolution of $\vec{\mathcal{B}}$ was known in systems that depend on only two spatial coordinates. That result is extended to systems that depend on all three spatial coordinates. In three dimensional space, the practical importance of the non-reconnecting evolution of $\vec{\mathcal{B}}$ appears limited. When the evolution velocity of $\vec{\mathcal{B}}$ is chaotic, reconnection naturally occurs on a timescale that depends only logarithmically on any non-ideal effect that is diffusive, such as resistivity. + oai:arXiv.org:2509.14400v3 + physics.plasm-ph + astro-ph.SR + Tue, 23 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Linmi Tao, Donglai Tao, Ruiyang Liu, Yu Cheng, Yuezhi Zhou, Li Huo, Zuoxiang He, Ti Jiang, Jingmao Cui, Yuanbiao Wang, Guilan Hu, Xiangsong Zhang, Yongwei Pan, Ye Yuan, Yun Liu + Allen H Boozer - What is glacier sliding - https://arxiv.org/abs/2407.13577 - arXiv:2407.13577v4 Announce Type: replace -Abstract: Glacier and ice-sheet motion is fundamental to glaciology. However, we still lack a consensus for the optimal way to relate basal velocity to basal traction for large-scale glacier and ice-sheet models (the 'sliding relationship'). Typically, a single tunable coefficient loosely connected to one or a limited number of physical processes is varied spatially to reconcile model output with observations. Yet, process-agnostic studies indicate that the suitability of a given sliding relationship depends on the setting. Here, we suggest that this arises from myriad overlapping setting- and scale-dependent sliding sub-processes, including complicated near-basal stress states not captured by large-scale models, reviewed here as comprising a basal 'sliding layer'. A corresponding 'bulk layer' then accounts for ice deformation only minimally influenced by bed properties. We provide a framework for incorporating arbitrarily many sub-processes within a given region -- separated into normal ('form drag') and tangential ('slip') resistance at the ice-bed interface, stressing that the maximum scale of cavitation is an important contributor to the division between the two. Under reasonable assumptions, our framework implies that sliding relationships should fall within a sum of regularised-Coulomb and power-law components, with a rough-smooth distinction proving more consequential in dictating sliding behaviour than a traditional hard-soft transition. - oai:arXiv.org:2407.13577v4 - physics.geo-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Energy transfer from MHD-scale slow-mode waves to kinetic-scale ion acoustic waves + https://arxiv.org/abs/2509.19763 + arXiv:2509.19763v2 Announce Type: replace +Abstract: Large-amplitude slow-mode waves are commonly observed near Earth's magnetopause. Recent observations show that these waves can occur simultaneously with kinetic-scale ion acoustic waves. The amplitude of the ion acoustic waves is enhanced near the magnetic field peaks of the slow-mode wave, suggesting that the slow-mode waves may drive the generation of ion acoustic waves. To test this hypothesis, we conduct a hybrid simulation using observation-based parameters. The simulation results demonstrate that large-amplitude slow-mode waves generate counter-streaming ion beams, which in turn excite ion acoustic waves and relax the ion beams. Our study reveals a clear energy transfer channel from MHD-scale slow-mode waves to kinetic-scale ion acoustic waves. + oai:arXiv.org:2509.19763v2 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Robert Law, David Chandler, Phillip Voigt, Ivan Utkin, Andreas Born + Xiaofei Shi, Xin An, Vassilis Angelopoulos - Patient-specific prediction of regional lung mechanics in ARDS patients with physics-based models: a validation study - https://arxiv.org/abs/2408.14607 - arXiv:2408.14607v2 Announce Type: replace -Abstract: The choice of lung protective ventilation settings for mechanical ventilation has a considerable impact on patient outcome, yet identifying optimal ventilatory settings for individual patients remains highly challenging due to the inherent inter- and intra-patient pathophysiological variability. In this validation study, we demonstrate that physics-based computational lung models tailored to individual patients can resolve this variability, allowing us to predict the otherwise unknown local state of the pathologically affected lung during mechanical ventilation. For seven ARDS patients undergoing invasive mechanical ventilation, physics-based, patient-specific lung models were created using chest CT scans and ventilatory data. By numerically resolving the interaction of the pathological lung with the airway pressure and flow imparted by the ventilator, we predict the time-dependent and heterogeneous local state of the lung for each patient and compare it against the regional ventilation obtained from bedside monitoring using Electrical Impedance Tomography. Excellent agreement between numerical simulations and experimental data was obtained, with the model-predicted anteroposterior ventilation profile achieving a Pearson correlation of 96% with the clinical reference data. Even when considering the regional ventilation within the entire transverse chest cross-section and across the entire dynamic ventilation range, an average correlation of more than 81% and an average root mean square error of less than 15% were achieved. The results of this first systematic validation study demonstrate the ability of computational models to provide clinically relevant information and thereby open the door for a truly patient-specific choice of ventilator settings on the basis of both individual anatomy and pathophysiology. - oai:arXiv.org:2408.14607v2 - physics.med-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Optical characterization of wavelength-shifting and scintillating-wavelength-shifting fibers + https://arxiv.org/abs/2509.20390 + arXiv:2509.20390v4 Announce Type: replace +Abstract: We report results of optical characterizations of new wavelength-shifting and scintillating-wavelength-shifting fibers EJ-182 and EJ-160 from Eljen Technology and compare them to the wavelength-shifting fiber BCF-91A from Saint-Gobain. The wavelength-dependence of attenuation was derived from spectral measurements confirming that the long attenuation length increases with wavelength, while short attenuation effects become less significant at longer wavelengths. The impact of the environmental refractive index was studied by immersing the EJ-160II fiber in water. Immersing the fiber in water reduced the overall light output and suppressed the short attenuation component, which can be explained by reduced light-collection efficiency due to the smaller refractive-index contrast between the fiber cladding and the surrounding medium. + oai:arXiv.org:2509.20390v4 + physics.ins-det + hep-ex + Tue, 23 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Maximilian Rixner, Maximilian Ludwig, Matthias Lindner, In\'ez Frerichs, Armin Sablewski, Karl-Robert Wichmann, Max-Carl Wachter, Kei W. M\"uller, Dirk Sch\"adler, Wolfgang A. Wall, Jonas Biehler, Tobias Becher + W. Bae, J. Cesar, K. Chen, J. Cho, D. Du, J. Edgar, L. Earthman, O. M. Falana, M. Gajda, C. Hurlbut, M. Jackson, K. Lang, C. Lee, J. Y. Lee, E. Liang, J. Liu, C. Maxwell, C. Murthy, D. Myers, S. Nguyen, T. O'Brien, M. Proga, T. Rodriguez, S. Syed, M. Zalikha, J. Zey - A consistent treatment of dynamic contact angles in the sharp-interface framework with the generalized Navier boundary condition - https://arxiv.org/abs/2411.10762 - arXiv:2411.10762v3 Announce Type: replace -Abstract: In this work, we revisit the Generalized Navier Boundary condition (GNBC) introduced by Qian et al.\ in the sharp interface Volume-of-Fluid context. We replace the singular uncompensated Young stress by a smooth function with a characteristic width $\varepsilon > 0$ that is understood as a physical parameter of the model. Therefore, we call the model the ``Contact Region GNBC'' (CR-GNBC). We show that the model is consistent with the fundamental kinematics of the contact angle transport described by Fricke, K\"ohne and Bothe. We implement the model in the geometrical Volume-of-Fluid solver Basilisk using a ``free angle'' approach. This means that the dynamic contact angle is not prescribed but reconstructed from the interface geometry and subsequently applied as an input parameter to compute the uncompensated Young stress. We couple this approach to the two-phase Navier Stokes solver and study the withdrawing tape problem with a receding contact line. It is shown that the model allows for grid-independent solutions and leads to a full regularization of the singularity at the moving contact line, which is in accordance with the thin-film equation subject to this boundary condition. In particular, it is shown that the curvature at the moving contact line is finite and mesh converging. As predicted by the fundamental kinematics, the parallel shear stress component vanishes at the moving contact line for quasi-stationary states (i.e. for $\dot{\theta}_d=0$) and the dynamic contact angle is determined by a balance between the uncompensated Young stress and an effective contact line friction. Furthermore, a non-linear generalization of the model is proposed, which aims at reproducing the Molecular Kinetic Theory of Blake and Haynes for quasi-stationary states. - oai:arXiv.org:2411.10762v3 - physics.flu-dyn + Visualising Quantum Entanglement Using Interactive Electronic Quantum Dice + https://arxiv.org/abs/2510.04931 + arXiv:2510.04931v2 Announce Type: replace +Abstract: Quantum entanglement remains a challenging concept to teach and visualise due to its microscopic and non-classical nature. We present innovative educational demonstration material consisting of electronic dice that simulate the properties of quantum entanglement through haptic interaction. The system uses displays, orientation sensors, and wireless communication to visualise key quantum mechanical principles such as superposition, measurement, and entanglement correlations. This analogy enables students to experience quantum phenomena through familiar objects, making abstract concepts more tangible. The dice support various educational scenarios, from basic entanglement demonstrations to more complex quantum key distribution experiments, and can be adapted for different educational levels from secondary school to undergraduate physics courses. Initial implementations demonstrate that the interactive nature of the Quantum Dice can help users develop an intuitive understanding of quantum mechanical principles. The low-cost, open source, and robust design makes Quantum Dice accessible to a wider range of educational institutions. + oai:arXiv.org:2510.04931v2 + physics.ed-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + B. Folkers, A. van Rossum, A. Brinkman, H. K. E. Stadermann + + + A Flux-Tunable Discrete Angular Filter + https://arxiv.org/abs/2510.06395 + arXiv:2510.06395v2 Announce Type: replace +Abstract: Recent work by Lawrie et al. [PRR 7, 023209 (2025)] introduced a non-diffracting resonant angular filter on a network of thin channels (modelled via quantum graph theory) that exhibits unit transmission of acoustic waves at a discrete, symmetry-paired set of incidence angles determined solely by the graph topology, while transmission at all other angles is strictly forbidden. In the present work, we study the same filtering geometry for waves governed by the magnetic Schr\"odinger equation rather than the classical wave equation. Using a phase shift induced by non-reciprocal wave propagation due to the presence of the magnetic potential and tuning $\delta$-type vertex boundary conditions, we make the previously topology-fixed discrete pass directions continuously tunable: both the transmission angle and the transmission coefficient become control parameters. The resulting flux-tunable angular filtering device replaces topology-constrained passbands with a programmable steering device, broadening the scope for wave-filter and beam-shaping applications. + oai:arXiv.org:2510.06395v2 + physics.app-ph math-ph math.MP - Mon, 22 Dec 2025 00:00:00 -0500 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by/4.0/ + 10.12693/APhysPolA.148.S25 + Acta Physica Polonica A, Vol. 148, No. 5 (2025) + Tristan M. Lawrie, Oliver M. Brown + + + Neutron-Assisted Breakdown Enhancement in $\beta$-Ga$_2$O$_3$ Schottky Diodes + https://arxiv.org/abs/2510.06415 + arXiv:2510.06415v2 Announce Type: replace +Abstract: This study demonstrates a substantial enhancement of breakdown voltage in $\beta$-Ga$_2$O$_3$ Schottky diodes through an approach that combines fast neutron irradiation with controlled post-irradiation electro-thermal annealing. Devices irradiated with 1 MeV neutrons at a high fluence of 1E15 n/cm^2 exhibited substantial degradation, including a drastic reduction in on-current and an increase in on-resistance. Electrothermal testing, conducted through simultaneous current-voltage (J-V) measurements and thermal annealing, resulted in significant recovery. After four cycles of electro-thermal testing, the devices demonstrated significant improvements in performance, with a substantial recovery of on-current and a reduction in on-resistance compared to the post-radiation condition, approaching pre-radiation levels. Most recovery occurred during the first two cycles, with diminishing improvements in later cycles, indicating that most thermally recoverable traps were mitigated early. Capacitance-voltage (C-V) measurements revealed a substantial reduction in carrier concentration, decreasing from 3.2E16 cm^-3 pre-radiation to 5.5E15 cm^-3 after the first electro-thermal testing cycle, indicating an over 82% reduction. Following the third cycle, the carrier concentration partially recovered to 9.9E15 cm^-3, reflecting a carrier removal rate of ~22 cm^-1. The breakdown voltage exhibited a remarkable enhancement, increasing from approximately 300 V to 1.28 kV (a ~325% improvement) after the first electro-thermal testing, attributed to the reduction in carrier concentration by compensating radiation-induced traps. Subsequent testing reduced breakdown voltage slightly to 940 V due to partial recovery of carrier concentration, but it remained significantly higher than pre-radiation levels. + oai:arXiv.org:2510.06415v2 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Saleh Ahmed Khan, Sudipto Saha, Ahmed Ibreljic, Stephen Margiotta, Jiawei Liu, Walid Amir, Surajit Chakraborty, Uttam Singisetti, A F M Anhar Uddin Bhuiyan + + + Single Sr Atoms in Optical Tweezer Arrays for Quantum Simulation + https://arxiv.org/abs/2510.19816 + arXiv:2510.19816v3 Announce Type: replace +Abstract: We report on the realization of a platform for trapping and manipulating individual $^{88}$Sr atoms in optical tweezers. A first cooling stage based on a blue shielded magneto-optical trap (MOT) operating on the $^1S_0$ -> $^1P_1$ transition at 461 nm enables us to trap approximately $4\times 10^6$ atoms at a temperature of 6.8 mK. Further cooling is achieved in a narrow-line red MOT using the $^1S_0$ -> $^3P_1$ intercombination transition at 689 nm, bringing $4\times 10^5$ atoms down to 5 $\mu$K and reaching a density of $\approx 10^{10}$ cm$^{-3}$. Atoms are then loaded into 813 nm tweezer arrays generated by crossed acousto-optic deflectors and tightly focused onto the atoms with a high-numerical-aperture objective. Through light-assisted collision processes we achieve the collisional blockade, which leads to single-atom occupancy with a probability of about $50\%$. The trapped atoms are detected via fluorescence imaging with a fidelity of $99.986(6)\%$, while maintaining a survival probability of $97(2)\%$. The release-and-recapture measurement provides a temperature of $12.92(5)$ $\mu$K for the atoms in the tweezers, and the ultra-high-vacuum environment ensures a vacuum lifetime higher than 7 min. These results demonstrate a robust alkaline-earth tweezer platform that combines efficient loading, cooling, and high-fidelity detection, providing the essential building blocks for scalable quantum simulation and quantum information processing with Sr atoms. + oai:arXiv.org:2510.19816v3 + physics.atom-ph + cond-mat.quant-gas + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Tomas Fullana, Yash Kulkarni, Mathis Fricke, St\'ephane Popinet, Shahriar Afkhami, Dieter Bothe, St\'ephane Zaleski + 10.3390/atoms14010001 + Atoms 2026, 14(1), 1 + Veronica Giardini, Luca Guariento, Andrea Fantini, Shawn Storm, Massimo Inguscio, Jacopo Catani, Giacomo Cappellini, Vladislav Gavryusev, Leonardo Fallani - Dual-Input Dynamic Convolution for Positron Range Correction in PET Image Reconstruction - https://arxiv.org/abs/2503.00587 - arXiv:2503.00587v4 Announce Type: replace -Abstract: Positron range (PR) blurring degrades positron emission tomography (PET) image resolution, particularly for high-energy emitters like gallium-68 (68 Ga). We introduce Dual-Input Dynamic Convolution (DDConv), a novel computationally efficient approach trained with voxel-specific PR point spread functions (PSFs) from Monte Carlo (MC) simulations and designed to be utilized within an iterative reconstruction algorithm to perform PR correction (PRC). By dynamically inferring local blurring kernels through a trained convolutional neural network (CNN), DDConv captures complex tissue interfaces more accurately than prior methods. Additionally, it also computes the transpose operator, ensuring consistency within iterative PET reconstruction. Comparisons with a state-of-the-art, tissue-dependent correction confirm the advantages of DDConv in recovering higher-resolution details in heterogeneous regions, including bone-soft tissue and lung-soft tissue boundaries. Experiments across digital phantoms and MC-simulated data show that DDConv offers near-MC accuracy and outperforms the state-of-the-art technique, namely spatially-variant and tissue-dependent (SVTD), especially in areas with complex material interfaces. Results from real phantom experiments further confirm DD-Conv's robustness and practical applicability: while both DD-Conv and SVTD performed similarly in homogeneous soft-tissue regions, DDConv provided more accurate activity recovery and sharper delineation at heterogeneous lung-soft tissue interfaces. Our code available at https://github.com/mellak/ddconv-prc. - oai:arXiv.org:2503.00587v4 - physics.med-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Third Harmonic Upconverted Full-Stokes Imaging with High-Efficiency Germanium Metasurface from MWIR to SWIR + https://arxiv.org/abs/2511.06214 + arXiv:2511.06214v3 Announce Type: replace +Abstract: Dielectric resonant metasurfaces can be utilized for efficient high harmonic generation, which has been explored here in this effort for a high-efficient Germanium metasurface for upconverted full-Stokes imaging at 1.33-micron wavelength by the third harmonic generation (THG) from the 4-micron fundamental wavelength. The internal TH conversion efficiency for the Ge film is about 1x10-5 % to 5.6x10-3 % and for the Ge-metasurface 1.5x10-4 % to 1.05x10-1 % for linearly polarized (LP) incidence, and 1.3x10-4 % to 6.1x10-2 % for circularly polarized (CP) incidence, for the optical intensity range 0.47 GW/cm2 to 16.8 GW/cm2 respectively. The effect of the Ge film height variation has been discussed and compared with transmission line theory for the nonlinear medium. The metasurface design pitch is suitably tuned for the anisotropic cross-triangles nanoantenna for analyzing the polarization states of the fundamental beam simultaneously. The effect of source intensity on TH conversion among the LP and CP states, flipping the nonlinear diffraction orders and incipient of new harmonics with intensity dependence and design limitations, has also been addressed. To my knowledge, with this type of metasurface design, this is the first approach for upconverted full-Stokes imaging. The benefit will be upconverted polarimetry of MWIR at SWIR, where uncooled efficient detectors are available for high-resolution thermal imaging. This efficient Ge-metasurface is exempt from TH transmission loss due to the size effect of assigning a phase gradient for polarization-dependent TH diffraction order generation and orthogonal transmission disparity. Integration of this type of metasurface for infrared image upconversion will open new possibilities for intense heat signature identification, especially for target recognition in next-generation infrared homing devices in surveillance and missile defense systems. + oai:arXiv.org:2511.06214v3 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Youness Mellak, Alexandre Bousse, Thibaut Merlin, \'Elise \'Emond, Mikko Hakulinen, Dimitris Visvikis + Hosna Sultana - Non-parametric kernel density estimation of magnitude distribution for the analysis of seismic hazard posed by anthropogenic seismicity - https://arxiv.org/abs/2503.04393 - arXiv:2503.04393v2 Announce Type: replace -Abstract: Frequent significant deviations of the observed magnitude distribution of anthropogenic seismicity from the Gutenberg-Richter relation require alternative estimation methods for probabilistic seismic hazard assessments. We evaluate five nonparametric kernel density estimation (KDE) methods on simulated samples drawn from four magnitude distribution models: the exponential, concave and convex bi-exponential, and exponential-Gaussian distributions. The latter three represent deviations from the Gutenberg-Richter relation due to the finite thickness of the seismogenic crust and the effect of characteristic earthquakes. The assumed deviations from exponentiality are never more than those met in practice. The studied KDE methods include Silverman's and Scott's rules with Abramson's bandwidth adaptation, two diffusion-based methods (ISJ and diffKDE), and adaptiveKDE, which formulates the bandwidth estimation as an optimization problem. We assess their performance for magnitudes from 2 to 6 with sample sizes of 400 to 5000, using the mean integrated square error (MISE) over 100,000 simulations. Their suitability in hazard assessments is illustrated by the mean of the mean return period (MRP) for a sample size of 1000. Among the tested methods, diffKDE provides the most accurate cumulative distribution function estimates for larger magnitudes. Even when the data is drawn from an exponential distribution, diffKDE performs comparably to maximum likelihood estimation when the sample size is at least 1000. Given that anthropogenic seismicity often deviates from the exponential model, we recommend using diffKDE for probabilistic seismic hazard assessments whenever a sufficient sample size is available. - oai:arXiv.org:2503.04393v2 - physics.geo-ph - stat.AP - Mon, 22 Dec 2025 00:00:00 -0500 + Beam-tracing and profile evolution for localised beams in inhomogeneous plasmas + https://arxiv.org/abs/2511.06255 + arXiv:2511.06255v3 Announce Type: replace +Abstract: We derive the beam tracing and profile evolution for the propagation of any localised beam with arbitrary profile through an inhomogeneous cold plasma. We recover standard Gaussian beam-tracing, with an additional PDE describing the evolution of the beam's profile as it propagates through the plasma. We then solve for generic families of solutions to the PDE using ladder operators, which can be chosen to reduce to Gauss-Hermite beams in homogeneous media. We importantly obtain an exact expression for the resulting beam profile, demonstrating that Hermite modes will generally evolve into a superposition of different modes during propagation through inhomogeneous plasmas, contrary to prior work on the subject. Importantly, this approach facilitates future analysis of the diagnostic signal received from arbitrary beams. + oai:arXiv.org:2511.06255v3 + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - 10.1007/s11600-025-01762-8 - Francis Tong, Stanis{\l}aw Lasocki, Beata Orlecka-Sikora + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Lewin B. S. Marsh, Felix I. Parra, Valerian H. Hall-Chen, Juan Ruiz Ruiz - Water activation using Ar-H$_2$ atmospheric pressure plasma jets - https://arxiv.org/abs/2504.12906 - arXiv:2504.12906v3 Announce Type: replace -Abstract: Whether for materials processing or medical applications, the use of atmospheric pressure plasma jets (APPJs) has emerged as a relevant alternative to conventional methods. Within the APPJs research field, the search for innovation aims not only to solve existing problems but also to explore novel options for generating plasma jets and find new possible applications. In this work, the properties of Ar-H$_2$ APPJs generated using two plasma sources that differ in the frequency, amplitude, and waveform of the generated voltage signal were studied through electrical, thermal, and optical characterization. The discharge parameters were analyzed as a function of the H$_2$ content in the gas mixture, with this parameter varying from 0\% to 3.5\%. Optical emission spectroscopy revealed that the same reactive species were produced for both plasma sources, except nitric oxide (NO), which was observed only for the source operated at a higher frequency (PS #1). Applications for water activation were performed without H$_2$ and with 3.5% H$_2$ in the gas mixture. The results of water treatment revealed that ammonia is also produced when H$_2$ is added to the working gas. This finding suggests that the water treated by a Ar-H$_2$ plasma jet can be an attractive option for use in agriculture. - oai:arXiv.org:2504.12906v3 + Conceptual design of Thomson scattering system with high wavelength resolution in magnetically confined plasmas for electron phase-space measurements + https://arxiv.org/abs/2511.06330 + arXiv:2511.06330v2 Announce Type: replace +Abstract: We discuss the conceptual design of a spatially-resolved spectroscopy system of Thomson scattering with high wavelength resolution capable of measuring the shape of electron velocity distribution functions in magnetically confined plasmas. We design a spatially-resolved spectrometer with 2560 wavelength channels. The estimated number of scattered photons in a single spectrometer channel is much larger than unity under the experimental setup and plasma parameters of the Compact Helical Device (CHD), indicating sufficient photon statistics for single-shot measurements. Simulations of the scattered spectra show that the signal-to-noise ratio exceeds 5 even under the most unfavorable conditions expected in CHD at full spectral resolution, and further improves with post-processing pixel binning. Bayesian inference applied to the simulated spectra demonstrates that the inferred plasma parameters agree with the input values within the estimated uncertainties. Comparisons between spectra generated from non-Maxwellian electron velocity distribution functions and their Maxwellian fits indicate that deviations from Maxwellian distributions can be identified using the proposed system. + oai:arXiv.org:2511.06330v2 physics.plasm-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1016/j.vacuum.2025.115027 - Vacuum, vol. 246 (2026), p. 115027 - Fellype do Nascimento, Ananias Alves Barbosa, Konstantin Georgiev Kostov + http://creativecommons.org/licenses/by/4.0/ + Kentaro Sakai, Kentaro Tomita, Takeo Hoshi, Akito Nakano, Motoshi Goto, Kenichi Nagaoka, Ryo Yasuhara - The Dual Nature of Body-Axis Formation in Hydra Regeneration: Polarity-Morphology Concurrency - https://arxiv.org/abs/2504.20603 - arXiv:2504.20603v2 Announce Type: replace -Abstract: The formation of a body-axis is central to animal development and involves both polarity and morphology. While polarity is traditionally associated with biochemical patterning, the morphological aspect of axis formation remains elusive. In regenerating Hydra tissues, we find that morphological evolution in all tissue samples depends on inherited positional information from the donor axis, and a foot precursor emerges early in the process. From the onset of regeneration, the Ca2+ excitations that drive actomyosin forces for tissue reshaping follow a gradient aligned with the head-foot polarity direction. We conclude that polarity and morphological axis progression occur concurrently through interlinked processes, and that the foot plays a dominant role in this process, a role usually attributed to the head organizer. A simple toy model accounts for the observed regeneration dynamics and illustrates the mechanochemical integration of polarity and morphogenesis. We expect the insights from Hydra to be relevant to broader developmental systems. - oai:arXiv.org:2504.20603v2 - physics.bio-ph - Mon, 22 Dec 2025 00:00:00 -0500 + GRANITE: High-Resolution Imaging and Electrical Qualification of Large-Area TPC Electrodes + https://arxiv.org/abs/2511.11401 + arXiv:2511.11401v3 Announce Type: replace +Abstract: Next-generation dual-phase time projection chambers (TPCs) for rare event searches will require large-scale, high-precision electrodes. To meet the stringent requirements for high-voltage performance of such an experiment, we have developed a scanning setup for comprehensive electrode quality assurance. The system is built around the GRANITE (Granular Robotic Assay for Novel Integrated TPC Electrodes) facility: a gantry robot on top of a $2.5\,\text{m}\times1.8\,\text{m}$ granite table, equipped with a suite of non-contact metrology devices. + We developed a coaxial wire scanning head to measure and correlate localized high-voltage discharge currents in air with high-resolution surface images. We find that the identified discharge 'hotspots' are transient and show no significant correlation with static visual features. Next, we established a quantitative relationship between artificially induced abrasive surface damage on the wires and a reduction in the discharge inception voltage. This work provides a novel non-invasive tool for qualifying wires dedicated for use in electrodes for future low-background experiments. + oai:arXiv.org:2511.11401v3 + physics.ins-det + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Oded Agam, Erez Braun + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Shumit A. Mitra, Alexander Deisting, Jan Lommler, Uwe Oberlack, Fabian Piermaier, Quirin Weitzel, Daniel Wenz - Beyond Force Metrics: Pre-Training MLFFs for Stable MD Simulations - https://arxiv.org/abs/2506.14850 - arXiv:2506.14850v3 Announce Type: replace -Abstract: Machine-learning force fields (MLFFs) have emerged as a promising solution for speeding up ab initio molecular dynamics (MD) simulations, where accurate force predictions are critical but often computationally expensive. In this work, we employ GemNet-T, a graph neural network model, as an MLFF and investigate two training strategies: (1) direct training on MD17 (10K samples) without pre-training, and (2) pre-training on the large-scale OC20 dataset followed by fine-tuning on MD17 (10K). While both approaches achieve low force mean absolute errors (MAEs), reaching 5 meV/A per atom, we find that lower force errors do not necessarily guarantee stable MD simulations. Notably, the pre-trained GemNet-T model yields significantly improved simulation stability, sustaining trajectories up to three times longer than the model trained from scratch. By analyzing local properties of the learned force fields, we find that pre-training produces more structured latent representations, smoother force responses to local geometric changes, and more consistent force differences between nearby configurations, all of which contribute to more stable and reliable MD simulations. These findings underscore the value of pre-training on large, diverse datasets to capture complex molecular interactions and highlight that force MAE alone is not always a sufficient metric of MD simulation stability. - oai:arXiv.org:2506.14850v3 - physics.chem-ph - cs.LG - Mon, 22 Dec 2025 00:00:00 -0500 + 100 Mfps ghost imaging with wavelength division multiplexing + https://arxiv.org/abs/2511.12049 + arXiv:2511.12049v2 Announce Type: replace +Abstract: Ghost imaging (GI) and single-pixel imaging (SPI) techniques enable image reconstruction without spatially resolved detectors, offering unique access to wide spectral ranges and challenging imaging environments. Yet, their adoption has been limited by the slow generation of mask patterns, which constrains achievable frame rates. Here, we demonstrate ultrafast GI that achieves a spatial-temporal information flux of 78.4 gigapixels per second across five wavelengths, which is at least two orders of magnitude larger than that reported for previous training-data-free GI approaches. This breakthrough is enabled by 25 GHz speckle pattern switching and allows parallelizing the pattern illumination using a wavelength-division multiplexing (WDM) technique. We show that the proposed approach is capable of reconstructing 28$\times$28-pixel images at the exposure time of 10 ns, achieving 100 megaframes per second (Mfps), and demonstrate the GI of a microsecond-scale dynamic event. This approach opens avenues for studying rapid processes in physics, chemistry, and biology, where conventional cameras are limited by detector bandwidth, readout speed, or cost. + oai:arXiv.org:2511.12049v2 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Shagun Maheshwari, Zhengxian Tang, Janghoon Ock, Adeesh Kolluru, Amir Barati Farimani, John R. Kitchin + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Shin Motooka, Noriki Komori, Tomoaki Niiyama, Satoshi Sunada - Collective effects of neighbouring melting ice objects - https://arxiv.org/abs/2506.16926 - arXiv:2506.16926v2 Announce Type: replace -Abstract: We present a study on the melting dynamics of neighbouring ice bodies by means of idealised simulations, focusing on collective effects, with the goal of obtaining fundamental insight into how collective interactions influence the melting of ice. Two neighbouring (vertically or horizontally aligned), square-shaped, and equally sized ice objects (size on the order of centimetres) are immersed in quiescent fresh water at a temperature of 20{\deg}C. By performing two-dimensional direct numerical simulations, and using the phase-field method to model the phase change, the collective melting of these objects is studied. When the objects are horizontally aligned, no significant influence of the neighbouring object on the melting time is observed. On the other hand, when vertically aligned, though the melting of the upper object is mostly unaffected, the melting time and the morphology of the lower ice body strongly depends on the initial inter-object distance. We report that the melting of the bottom object can be enhanced by more than 10%, or delayed more than 20%, displaying a non-monotonic dependence on the initial object size. We show that this behaviour results from a non-trivial competition between layering of cold fluid, which lowers the heat transfer, and convective flows, which favour mixing and heat transfer. For this melting in mixed convection, we were able to collapse our data onto a single curve. - oai:arXiv.org:2506.16926v2 - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + 3D printed waveguides for optogenetics applications: design optimization and optical characterization + https://arxiv.org/abs/2511.15420 + arXiv:2511.15420v3 Announce Type: replace +Abstract: Optogenetics has emerged as a powerful tool for disease modeling, enabling precise control of cellular activities through light stimulation and providing a valuable insights into disease mechanisms and therapeutic possibilities. Innovative materials and technologies such as micro-LEDs, optical fibers and micro/nano probes have been developed to allow precise spatial and temporal control of light delivery to target cells. Recent advances in 3D printing have further enhanced optogenetic applications by enabling the fabrication of implantable, customizable, and miniaturized light stimulation systems with high spatial resolution. In this study, we introduce a novel concept of a 3D printed light delivery system for brain organoid stimulation exploring the capabilities of projection microstereolithography (P$\mu$SL). We characterized the optical properties of the high-resolution acrylate-based 3D print resin, i.e., refractive index and extinction coefficient, to evaluate if the light transmission efficiency might limit the performance of the optogenetic stimulation systems. Finite element method simulations were employed to optimize the 3D printed design. An optogenetic setup was developed for optimal light delivery, and initial tests with optogenetically modified cells showed light-induced dopamine release with a stimulation efficiency of 2.8\%, confirming the 3D printed waveguide functionality and guiding future optimization. Our results demonstrate that this light stimulation tool offers strong potential for advancing customizable optogenetic applications. + oai:arXiv.org:2511.15420v3 + physics.optics + physics.app-ph + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Sof\'ia Angriman, Detlef Lohse, Roberto Verzicco, Sander G. Huisman + Giorgio Scordo, Kostas Kanellopulos, Surangrat Thongkorn, Samuel Tavares da Silva Maraschin, Kambiz Ghaseminasab, Evgeniy Shkondin, Deepshika Arasu, Stephan Sylvest Keller, Arto Rainer Heiskanen, Marta Perez Pereira, Jenny Emn\'eus - The gradual transformation of inland areas -- human plowing, horse plowing and equity incentives - https://arxiv.org/abs/2507.00067 - arXiv:2507.00067v3 Announce Type: replace -Abstract: Many modern areas have not learned their lessons and often hope for the wisdom of later generations, resulting in them only possessing modern technology and difficult to iterate ancient civilizations. At present, there is no way to tell how we should learn from history and promote the gradual upgrading of civilization. Therefore, we must tell the history of civilization's progress and the means of governance, learn from experience to improve the comprehensive strength and survival ability of civilization, and achieve an optimal solution for the tempering brought by conflicts and the reduction of internal conflicts. Firstly, we must follow the footsteps of history and explore the reasons for the long-term stability of each country in conflict, including providing economic benefits to the people and means of suppressing them; then, use mathematical methods to demonstrate how we can achieve the optimal solution at the current stage. After analysis, we can conclude that the civilization transformed from human plowing to horse plowing can easily suppress the resistance of the people and provide them with the ability to resist; The selection of rulers should consider multiple institutional aspects, such as exams, elections, and drawing lots; Economic development follows a lognormal distribution and can be adjusted by population mean and standard deviation. Using a lognormal distribution with the maximum value to divide equity can adjust the wealth gap. - oai:arXiv.org:2507.00067v3 - physics.soc-ph - cs.CE - econ.GN - q-fin.EC - Mon, 22 Dec 2025 00:00:00 -0500 + Disentangling Brillouin's negentropy law of information and Landauer's law on data erasure + https://arxiv.org/abs/2512.02086 + arXiv:2512.02086v2 Announce Type: replace +Abstract: The link between information and energy introduces the observer and their knowledge into the understanding of a fundamental quantity of physics. Two approaches compete to account for this link, Brillouin's negentropy law of information and Landauer's law on data erasure, which are often confused. The first, based on the Clausius' inequality and Shannon's mathematical results is very robust, while the second, based on the simple idea that information needs a material embodiment (data-bits) is today perceived as more physical and prevails. In this paper, we show that Landauer's idea results from a confusion between information (a global emergent concept) and data (a local material object). This confusion leads to many inconsistencies and is incompatible with thermodynamics and information theory. The reason it prevails is interpreted to be due to a frequent tendency of materialism towards reductionism, neglecting emergence and seeking to eliminate the role of the observer. A paradoxical trend given that it is often accompanied by the materialist idea that all scientific knowledge nevertheless originates from observation. Information and entropy are actually emergent quantities introduced in the theory by convention. + oai:arXiv.org:2512.02086v2 + physics.gen-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Didier Lairez + + + Conservation of Momentum and Energy in the Lorenz-Abraham-Dirac Equation of Motion + https://arxiv.org/abs/2512.02960 + arXiv:2512.02960v2 Announce Type: replace +Abstract: After a brief review of the modified causal Lorentz-Abraham classical equation of motion for an extended charged sphere and its limit to the mass-renormalized modified causal Lorentz-Abraham-Dirac equation of motion as the radius of the charged sphere approaches zero, a concise derivation is given for the conditions on the velocity and external force required for these modified equations of motion to satisfy conservation of momentum and energy. The solutions to the unmodified and modified LAD equations of motion as well as the Landau-Liftshitz approximate solution to the unmodified LAD equation of motion are obtained for a charge traveling through a parallel-plate capacitor. + oai:arXiv.org:2512.02960v2 + physics.class-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Hongfa Zi, Zhen Liu + Arthur D. Yaghjian - Quantum Quasinormal Mode Theory for Dissipative Nano-Optics and Magnetodielectric Cavity Quantum Electrodynamics - https://arxiv.org/abs/2507.05233 - arXiv:2507.05233v3 Announce Type: replace -Abstract: The unprecedented pace of evolution in nanoscale architectures for cavity quantum electrodynamics (cQED) has posed crucial challenges for theory, where the quantum dynamics arising from the non-perturbative dressing of matter by cavity electric and magnetic fields, as well as the fundamentally non-hermitian character of the system are to be treated without significant approximation. The lossy electromagnetic resonances of photonic, plasmonic or magnonic nanostructures are described as quasinormal modes (QNMs), whose properties and interactions with quantum emitters and spin qubits are central to the understanding of dissipative nano-optics and magnetodielectric cQED. Despite recent advancements toward a fully quantum framework for QNMs, a general and universally accepted approach to QNM quantization for arbitrary linear media remains elusive. In this work, we introduce a unified theoretical framework, based on macroscopic QED and complex coordinate transformations, that achieves QNM quantization for a wide class of spatially inhomogeneous, dissipative (with possible gain components) and dispersive, linear, magnetodielectric resonators. The complex coordinate transformations equivalently convert the radiative losses into non-radiative material dissipation, and via a suitable transformation that reflects all the losses of the resonator, we define creation and annihilation operators that allow the construction of modal Fock states for the joint excitations of field-dressed matter. By directly addressing the intricacies of modal loss in a fully quantum theory of magnetodielectric cQED, our approach enables the exploration of modern, quantum nano-optical experiments utilizing dielectric, plasmonic, magnetic or hybrid cQED architectures, and paves the way towards a rigorous assessment of room-temperature quantum nanophotonic technologies without recourse to ad hoc quantization schemes. - oai:arXiv.org:2507.05233v3 - physics.optics + Quantum Simulations of Opinion Dynamics + https://arxiv.org/abs/2512.03770 + arXiv:2512.03770v2 Announce Type: replace +Abstract: Consensus formation is a central problem in collective behavior. In this work, we develop quantum models of opinion dynamics that can be exactly solved and implemented on current quantum hardware. By exploiting quantum superposition, measurement-induced state collapse, and entanglement, our framework captures key features of opinion evolution and allows a systematic investigation of how network connectivity shapes consensus formation. We demonstrate our approach using practical quantum circuits and validate representative cases on IBM Quantum devices for the open-chain. Further results demonstrate that quantum platforms can serve as a viable framework for simulating opinion dynamics and for probing the interplay between leadership, network structure, and collective behavior. + oai:arXiv.org:2512.03770v2 + physics.soc-ph quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Lars Meschede, Daniel D. A. Clarke, Ortwin Hess + http://creativecommons.org/licenses/by-sa/4.0/ + Xingyu Guo, Xiaoyang Wang, Lingxiao Wang - Emergent dynamical scaling in the inviscid limit of 3D stochastic Navier-Stokes equation with thermal noise - https://arxiv.org/abs/2507.05811 - arXiv:2507.05811v2 Announce Type: replace -Abstract: In this work, we investigate the Navier-Stokes equation in the presence of thermal noise, both at finite viscosity (revisiting the seminal work by Forster-Nelson-Stephen) and in the inviscid limit, which has not yet been explored. We determine the space-time velocity correlations in this dynamics, using functional renormalisation group and direct numerical simulations. While spectrally truncated three-dimensional Euler flows reach a stationary equilibrium state, they exhibit non-trivial temporal correlations. We show that these non-trivial correlations persist for small but finite viscosity, yielding an emergent $\tau\sim k^{-1}$ dynamical scaling, where $\tau$ is the decorrelation time. We characterise the crossover from the scaling $\tau\sim 1/(\nu k^2)$, expected at large viscosity, to the scaling $\tau\sim 1/(u_{\rm rms}k)$ found in the inviscid limit. - oai:arXiv.org:2507.05811v2 + An Euler-Lagrangian Multiphysics Coupling Framework for Particle-Laden High-Speed Flows + https://arxiv.org/abs/2512.06548 + arXiv:2512.06548v4 Announce Type: replace +Abstract: Particle-laden effects in high-speed flows require a coupled Euler and Lagrangian prediction technique with varying fidelity of thermochemical models, depending on the simulation conditions of interest. This requirement makes the development of a conventional monolithic solver challenging to manage the different fidelity of the thermochemical models within a single computational framework. To address this, the present study proposes a multi-solver framework for the coupled Euler-Lagrangian predictions applicable to various particle-laden high-speed flow conditions. Volumetric and surface couplings are established between a particle solver ORACLE (OpenFOAM-based lagRAngian CoupLEr) and a thermochemical nonequilibrium flow solver based on an adaptable data exchange algorithm. The developed framework is then validated by predicting particle-laden supersonic nozzle flows and aerothermal heating around a hypersonic Martian atmospheric entry capsule. Finally, a quasi-1D approximation is proposed in conjunction with a surrogate method to efficiently and accurately predict particle-laden surface erosion, with quantified parametric uncertainty, for hypersonic aerothermal characterization. + oai:arXiv.org:2512.06548v4 physics.flu-dyn - cond-mat.stat-mech - Mon, 22 Dec 2025 00:00:00 -0500 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1098/rsta.2025.0035 - Phil. Trans. A (2026) - Liubov Gosteva, Marc Brachet, L\'eonie Canet + Hyeon Woo Nam, Tae Woong Jeong, Sung Min Jo - Fermion selective tests of new physics with the bound electron g-factor - https://arxiv.org/abs/2508.00685 - arXiv:2508.00685v2 Announce Type: replace -Abstract: The use of high-precision measurements of the $g$ factor of single-electron ions is considered as a detailed probe for physics beyond the Standard Model. The contribution of the exchange of a hypothetical force-carrying scalar boson to the $g$ factor is calculated for the ground state of H-like ions and used to derive bounds on the parameters of that force. Similarly to the isotope shift, we employ the nuclide shift, i.e. the difference for elements with different proton and/or neutron numbers, in order to increase the experimental sensitivity to the new physics contribution. In particular we find, combining available measurements with current precision with different ions, that the coupling constant for the interaction between an electron and a proton can be constrained up to three orders of magnitude better than with the best current atomic data and theory. - oai:arXiv.org:2508.00685v2 - physics.atom-ph - hep-ph - Mon, 22 Dec 2025 00:00:00 -0500 + A Tri-Band Shared-Aperture Base Station Antenna Array Covering 5G Mid-Band and 6G Centimetric Wave Band + https://arxiv.org/abs/2512.07392 + arXiv:2512.07392v2 Announce Type: replace +Abstract: This work proposes a tri-band shared-aperture antenna array with three wide bands, covering the 5G mid-band and the 6G centimetric band, which is a promising candidate for future 6G base station antennas. The challenge of suppressing interferences, including scattering and coupling, in the tri-band array is holistically addressed across wide bands. Guided by characteristic mode analysis (CMA), a segmented spiral radiator is efficiently developed to mitigate scattering and coupling at high frequencies while preserving radiation performance at low frequencies. Compared to a conventional tube radiator, the proposed spiral exhibits a reduced radar cross-section (RCS) over an ultra-wide range of 4.7-21.5 GHz (128.2%). With the aid of serial resonators, impedance matching of the segmented-spiral-based dipole antenna is achieved across the low band (LB) of 3.05-4.68 GHz (42.2%), spanning the 5G band 3.3-4.2 GHz. Moreover, suppressors are placed near the LB ports to further reduce the cross-band coupling. Middle band (MB) and high band (HB) antennas operate in 6.2-10.0 GHz (46.9%) and 10.0-15.6 GHz (43.8%), respectively, collectively covering the anticipated 5G-Advanced and 6G centimetric band of 6.425-15.35 GHz. Both the MB and HB antennas employ a planar magnetoelectric (ME) dipole structure, which prevents common-mode resonances in the LB and MB, and mitigates the scattering from the MB antenna in the HB. In this tri-band array, radiation patterns remain undistorted across the LB, MB, and HB, and the isolation between any two ports exceeds 20 dB over all three bands. + oai:arXiv.org:2512.07392v2 + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - 10.1103/zyb6-lvy8 - Matteo Moretti, Christoph H. Keitel, Zolt\'an Harman + Shang-Yi Sun, Hai-Han Sun, Can Ding, Y. Jay Guo - Mean velocity profile in stably stratified turbulent channel flow - https://arxiv.org/abs/2508.03349 - arXiv:2508.03349v3 Announce Type: replace -Abstract: The Monin-Obukhov Similarity Theory (MOST) is a cornerstone of atmospheric science for describing turbulence in stable boundary layers. Extending MOST to stably stratified turbulent channel flows, however, is non-trivial due to confinement by solid walls and the much smaller turbulent length scales involved. In this study, we investigate the applicability of MOST in closed channels and identify where and to what extent the theory remains valid. A key finding is that the ratio of the half-channel height to the Obukhov length serves as a governing parameter for identifying distinct flow regions and determining the scaling of the mean velocity within them. Hence, we propose a closure relation to estimate this ratio directly from the governing input parameters: friction Reynolds and friction Richardson numbers ($Re_{\tau}$ and $Ri_{\tau}$). The framework is tested against a series of direct numerical simulations (DNS) across a range of $Re_{\tau}$ and $Ri_{\tau}$. The reconstructed velocity profiles enable accurate prediction of the skin friction coefficient crucial for quantifying pressure losses in stratified flows in engineering applications. - oai:arXiv.org:2508.03349v3 - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Metabolic rate beyond the 3/4 law + https://arxiv.org/abs/2512.08031 + arXiv:2512.08031v2 Announce Type: replace +Abstract: In earlier work, we introduced a discrete Fibonacci-based ontogenetic model in which the metabolic scaling exponent $b(n)$ is treated as a dynamic function of an organism's developmental stage, and we estimated $b(n)$ for selected mammalian species. In the present article, we revisit this framework with a complementary aim. Rather than proposing new parameter estimates or statistical fits, we provide a didactic, step-by-step reconstruction of the derivation that leads from the recursive growth hypothesis to analytical expressions for the stage-dependent exponent $b(n)$. Building directly on these previously obtained exponents, we then incorporate Kleiber's classical result into the model by interpreting the constant $70$ in the law $B \approx 70\,M^{3/4}$ (with $B$ denoting basal metabolic rate and $M$ body mass) as a metabolic "anchoring point". This yields a stage-dependent basal metabolic rate of the form $B(n) = 70\,M^{b(n)}$, which defines an ontogenetic metabolic trajectory linking recursive growth to changes in scaling. We show, at a conceptual level, how this anchored formulation can describe a shift from strongly sublinear behavior at early stages towards an almost linear regime as development proceeds, while still producing basal rates that are compatible, in order of magnitude, with those reported for mammals of different sizes. In this way, the paper offers a self-contained and pedagogical presentation of the model, emphasizing how ontogenetic changes in metabolic rate can be understood through the combined ideas of Fibonacci-like recursion and metabolic anchoring. + oai:arXiv.org:2512.08031v2 + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - 10.1017/jfm.2025.10972 - Journal of Fluid Mechanics, Volume 1025, 25 December 2025, A44 - Sanath Kotturshettar, Pedro Costa, Rene Pecnik + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Dorilson Silva Cambui - The Impact of Thermal Fields on Rydberg Atom Radio Frequency Sensors - https://arxiv.org/abs/2508.17506 - arXiv:2508.17506v2 Announce Type: replace -Abstract: Rydberg atom radio frequency sensors are unique in a number of ways, including possessing extraordinary carrier bandwidth, self-calibration and accuracy. In this paper, we examine the impact of thermal radiation on Rydberg atom sensors. Antennas are limited by their thermal background, while Rydberg atom sensors are coherent sensors. Incoherent thermal radiation does not limit Rydberg atom sensors in the same way as an antenna. The primary consequence of a thermal radiation field on Rydberg atom sensors is to decrease their coherence, as the decay rates of the Rydberg states used for sensing the radio frequency field are increased due to the thermal field, i.e. blackbody, modification of the atomic decay rates. Thermal and coherent field excitation are fundamentally different in that thermal fields produce statistically independent excitations with well-defined frequency, polarization, and propagation direction, while coherent states are coherent superpositions of photon number states. Consequently, thermal fields do not contribute to the coherences of the density matrix that are used for Rydberg atom sensing, except for damping them. - oai:arXiv.org:2508.17506v2 - physics.atom-ph - Mon, 22 Dec 2025 00:00:00 -0500 + The meaning of "Big Bang" + https://arxiv.org/abs/2512.09950 + arXiv:2512.09950v2 Announce Type: replace +Abstract: What does ``Big Bang'' actually mean? What was the origin of these two words? It has often been said that the expression ``Big Bang'' began as an insult. Even if this were true, it would be just an irrelevant part of the whole issue. There are many more aspects hidden under this name, and which are seldom explained. They will be discussed in this work. In order to frame the analysis, help will be sought from the highly authoritative voices of two exceptional writers: William Shakespeare and Umberto Eco. Both Shakespeare and Eco have explored the tension existing between words and the realities they name. With the conclusion that names are, in general, just labels, simple stickers put to identify things. And this includes those given to great theorems or spectacular discoveries. Stigler's law of eponymy is recalled to further substantiate those statements. These points will be at the heart of the investigation carried out here, concerning the very important concept of ``Big Bang''. Everybody thinks to know what ``the Big Bang'' is, but only very few do know it, in fact. When Fred Hoyle first pronounced these two words together, on a BBC radio program, listeners were actually left with the false image that Hoyle was trying to destroy. That is, the tremendous explosion of Lema\^itre's primeval atom (or cosmic egg), which scattered all its enormous matter and energy content throughout the rest of the Universe. This image is absolutely wrong! As will be concluded, today the label ``Big Bang'' is used in several different contexts: (a) the Big Bang Singularity; (b) as the equivalent of cosmic inflation; (c) speaking of the Big Bang cosmological model; (d) to name a very popular TV program; and more. + oai:arXiv.org:2512.09950v2 + physics.pop-ph + astro-ph.CO + gr-qc + math-ph + math.MP + physics.hist-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Channprit Kaur, Pinrui Shen, Donald Booth, Andrew Todd, James P. Shaffer + http://creativecommons.org/licenses/by/4.0/ + Emilio Elizalde - Global Forecasting of Tropical Cyclone Intensity Using Neural Weather Models - https://arxiv.org/abs/2508.17903 - arXiv:2508.17903v3 Announce Type: replace -Abstract: Numerical Weather Prediction (NWP) models that integrate coupled physical equations forward in time are the traditional tools for simulating atmospheric processes and forecasting weather. With recent advancements in deep learning, AI-based Weather Prediction models that rely on neural network architectures$\unicode{x2013}$Neural Weather Models (NeWMs)$\unicode{x2013}$have emerged as competent medium-range NWP emulators, with performances that compare favorably to state-of-the-art NWP models. However, they are commonly trained on reanalyses with limited spatial resolution (e.g., 0.25{\deg} horizontal grid spacing), which smooths out key features of weather systems. For example, tropical cyclones (TCs)$\unicode{x2013}$among the most impactful weather events due to their devastating effects on human activities$\unicode{x2013}$are challenging to forecast, as extrema are smoothed in deterministic forecasts at 0.25{\deg} resolution. To address this, we use our best observational estimates of wind gusts and minimum sea level pressure to train a hierarchy of post-processing models on NeWM outputs. Applied to Pangu-Weather and FourCastNet v2, the post-processing models produce accurate and reliable forecasts of TC intensity up to five days ahead. Our post-processing algorithm is tracking-independent, preventing full misses, and we demonstrate that even linear models extract predictive information from NeWM outputs beyond what is encoded in their initial conditions. While spatial masking improves probabilistic forecast consistency, we do not find clear advantages of convolutional architectures over simple multilayer perceptrons for our NeWM post-processing purposes. Overall, by combining the efficiency of NeWMs with a lightweight, tracking-independent postprocessing framework, our approach improves the accessibility of global TC intensity forecasts, marking a step toward their democratization. - oai:arXiv.org:2508.17903v3 - physics.comp-ph - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Design of Microlens Arrays for Thermal Imaging with Spintronic Poisson Bolometers + https://arxiv.org/abs/2512.12491 + arXiv:2512.12491v2 Announce Type: replace +Abstract: Infrared (IR) detectors are widely used for their ability to sense thermal radiation. Recently, a room-temperature infrared detector known as the spintronic Poisson bolometer was introduced. Operating in a probabilistic regime governed by Poissonian counting statistics, it establishes a fundamentally different detection mechanism with the potential to relax conventional sensitivity limits. While offering fast digital readout, its sensitivity is currently limited by a small active area and array fill factor. In this work, we present design guidelines for spherical plano-convex microlens arrays that enhance light collection in spintronic Poisson bolometer arrays. Using FDTD simulations of aluminum oxide microlenses, we analyze focal properties, collection efficiency, and concentration factor in the mid-wave infrared (MWIR). Guided by the simulations, we fabricate a microlens array sample to demonstrate that the chosen geometrical parameters are realistic and compatible with the fabrication process. A radiometric-stochastic model is used to quantify the resulting sensitivity improvements. + oai:arXiv.org:2512.12491v2 + physics.optics + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Milton Gomez, Louis Poulain--Auzeau, Alexis Berne, Tom Beucler + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Ziyi Yang, Leif Bauer, Zubin Jacob - Role of quantum dynamics in coherent and incoherent radiation during tunneling ionization - https://arxiv.org/abs/2508.20619 - arXiv:2508.20619v2 Announce Type: replace -Abstract: Radiation during strong-field tunneling ionization is investigated. The spontaneous as well as the coherent components of the radiation are calculated describing the ionization dynamics via the strong field approximation and the role of the quantum dynamics at tunneling is analyzed. The competition between different mechanisms in different spectral regions is examined. Transition-like radiation (Brunel radiation) is dominated at low-frequencies, Thomson scattering at the laser frequency, and radiative recombination via the three-step process at high-order harmonics. To distinguish the role of the quantum dynamics, simple man Drude models are developed for the coherent as well as for spontaneous radiation, which are based on the electron trajectory out of the tunneling barrier. The quantum dynamics is shown to modify the coherent Brunel radiation for near-zero-frequencies in asymmetric laser pulses. The significant role of free-free transitions is demonstrated for the spontaneous radiation in the low-frequency region. - oai:arXiv.org:2508.20619v2 - physics.atom-ph - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + First-return statistics in bounded radiative transport: A Motzkin polynomial framework + https://arxiv.org/abs/2512.13986 + arXiv:2512.13986v2 Announce Type: replace +Abstract: A photon entering a scattering medium executes a three-dimensional random walk determined by the Henyey-Greenstein phase function. The photon either reaches the boundary for a first passage or is absorbed. Projecting the walk onto the axial direction produces a one-dimensional alternating process whose peaks and valleys correspond to changes in the sign of the projected step. This reduction preserves first-return and first-passage events and leads to a representation in terms of Motzkin-type polynomials. The analytical formulation is complete except for boundary-constrained return terms, which appear as high-order integrals. We treat these contributions with a single truncation factor determined from Monte Carlo simulations of first-return distributions over a wide range of anisotropy g and scattering steps ms. The resulting factor follows a Cauchy distribution. Incorporating it yields first-return probabilities in agreement with full three-dimensional Monte Carlo to within 2% for g<=0.7. The approach gives backscattering coefficients from phase-function integrals and provides an efficient alternative to full three-dimensional simulations for problems of radiative transport in semi-infinite media. + oai:arXiv.org:2512.13986v2 + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 replace http://creativecommons.org/licenses/by/4.0/ - Michael Klaiber, Karen Z. Hatsagortsyan, Christoph H. Keitel + Claude Zeller (Claude Zeller Consulting LLC), Robert Cordery (Fairfield University) - Characterisation of the first wafer-scale prototype for the ALICE ITS3 upgrade: the monolithic stitched sensor (MOSS) - https://arxiv.org/abs/2510.11463 - arXiv:2510.11463v3 Announce Type: replace -Abstract: This paper presents the characterisation and testing of the first wafer-scale monolithic stitched sensor (MOSS) prototype developed for the ALICE ITS3 upgrade that is to be installed during the LHC Long Shutdown 3 (2026-2030). The MOSS chip design is driven by the truly cylindrical detector geometry that imposes that each layer is built out of two wafer-sized, bent silicon chips. The stitching technique is employed to fabricate sensors with dimensions of 1.4 $\times$ 25.9 cm, thinned to 50 $\mu$m. The chip architecture, in-pixel front-end, laboratory and in-beam characterisation, susceptibility to single-event effects, and series testing are discussed. The testing campaign validates the design of a wafer-scale stitched sensor and the performance of the pixel matrix to be within the ITS3 requirements. The MOSS chip demonstrates the feasibility of the ITS3 detector concept and provides insights for further optimisation and development. - oai:arXiv.org:2510.11463v3 - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 + Mapping the Optical Landscape of a Squaraine Molecule in the Visible and Ultraviolet Energy Range + https://arxiv.org/abs/2512.14630 + arXiv:2512.14630v2 Announce Type: replace +Abstract: Although squaraine dyes are commonly praised as candidates for light-based applications, little is known about their excited state landscape beyond the low-energy visible light region. Our work aims for an improved understanding of the photophysical properties of squaraines at the example of N-isobutyl substituted anilino-squaraine (SQIB) by extending ground-state and excited-state absorption spectroscopy of the molecule into the ultraviolet up to 6.5~eV. In addition, we distinguish the relative transition dipole moments of the excited state absorption peaks with the help of transient absorption anisotropy experiments. To relate experimental features to specific states, we employ a set of ab initio methods including time-dependent density functional theory (TDDFT), the Bethe-Salpeter equation (BSE) and n-electron valence perturbation theory on top of a self-consistent complete active space (CASSCF/NEVPT2). Our assignment is complemented by vibronic simulations and a discussion of two-photon absorption measurements. Through this joint effort, we are able to provide a consistent picture of the optical behavior of SQIB across the visible and ultraviolet light regime, and assign a total of twelve electronically excited states to our experimental data. + oai:arXiv.org:2512.14630v2 + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Omar Abdelrahman, Gianluca Aglieri Rinella, Luca Aglietta, Giacomo Alocco, Matias Antonelli, Roberto Baccomi, Francesco Barile, Pascal Becht, Franco Benotto, Stefania Maria Beol\`e, Marcello Borri, Daniela Bortoletto, Naseem Bouchhar, Giuseppe Eugenio Bruno, Matthew Daniel Buckland, Szymon Bugiel, Paolo Camerini, Francesca Carnesecchi, Marielle Chartier, Domenico Colella, Angelo Colelli, Giacomo Contin, Giuseppe De Robertis, Wenjing Deng, Antonello Di Mauro, Vittorio Di Trapani, Maurice Donner, Ana Dorda Martin, Piotr Dorosz, Floarea Dumitrache, Lars D\"opper, Gregor Hieronymus Eberwein, Domenico Elia, Simone Emiliani, Laura Fabbietti, Tommaso Fagotto, Xiaochao Fang, Henrik Fribert, Roman Gernh\"auser, Piero Giubilato, Laura Gonella, Karl Gran Grodaas, Ola Slettevoll Groettvik, Vladimir Gromov, Malte Gr\"onbeck, Philip Hauer, Hartmut Hillemanns, Guen Hee Hong, Yu Hu, Minyoung Chris Hwang, Marc Alain Imhoff, Barbara Jacak, Daniel Matthew Jones, Antoine Junique, Filip K\v{r}\'i\v{z}ek, Jetnipit Kaewjai, Anouk Kaiser, Jesper Karlsson Gumprecht, Markus Keil, Bernhard Ketzer, Jiyoung Kim, Lena Kirchner, Kritsada Kittimanapun, Alex Kluge, Chinorat Kobdaj, Artem Kotliarov, Thanushan Kugathasan, Marc K\"onig, Paola La Rocca, Natthawut Laojamnongwong, Lukas Lautner, Corentin Lemoine, Long Li, Beatrice Eva Liang-Gilman, Francesco Licciulli, Sanghoon Lim, Bong-Hwi Lim, Jian Liu, Flavio Loddo, Matteo Lupi, Magnus Mager, Philipp Mann, Georgios Mantzaridis, Davide Marras, Paolo Martinengo, Silvia Masciocchi, Annalisa Mastroserio, Soniya Mathew, Serena Mattiazzo, Marius Wilm Menzel, Nicola Minafra, Frederic Morel, Alice Mulliri, Anjali Ila Nambrath, Rajendra Nath Patra, Iaroslav Panasenko, Styliani Paniskaki, Caterina Pantouvakis, Cosimo Pastore, Stefania Perciballi, Francesco Piro, Adithya Pulli, Alexander Rachev, Alexander Rachevski, Ivan Ravasenga, Felix Reidt, Michele Rignanese, Giacomo Ripamonti, Isabella Sanna, Valerio Sarritzu, Umberto Savino, Iain Sedgwick, Serhiy Senyukov, Danush Shekar, Sabyasachi Siddhanta, David Silvermyr, Walter Snoeys, Joey Staa, Alessandro Sturniolo, Miljenko \v{S}ulji\'c, Timea Szollosova, Daniel Tapia Takaki, Livia Terlizzi, Nicolas Tiltmann, Antonio Trifir\`o, Christina Tsolanta, Rosario Turrisi, Berkin Ulukutlu, Gianluca Usai, Isabelle Valin, Giovanni Vecil, Pedro Vicente Leitao, Anna Villani, Chunzheng Wang, Zhenyu Ye, Emma Rose Yeats, Asli Yelkenci, Zijun Zhao, Alessandra Zingaretti + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Narges Taghizade, Robert Schwarzl, Frederik Leinenbach, Maximilian Jeindl, Marvin F. Schumacher, Brunella Bardi, Arne L\"utzen, Manuela Schiek, Andreas W. Hauser, Peter Puschnig, Markus Koch, Andreas Windischbacher - Verification of Convergent-Divergent Nozzle Designs in Propulsion Aerospace Applications - https://arxiv.org/abs/2510.11667 - arXiv:2510.11667v3 Announce Type: replace -Abstract: The performance of convergent and divergent nozzles is critical in aerospace propulsion systems, where the efficient expansion of high-temperature, high-pressure gases directly impacts thrust generation. In this study, we investigate a series of nozzle geometries using numerical simulations in ANSYS Fluent, guided by classical compressible flow theory, initially developed by Ludwig Prandtl. The governing equations of conservation of mass, momentum, and energy are solved under steady-state conditions, with emphasis on shock formation, boundary-layer effects, and Mach number distributions across the nozzle throat and divergent section. Parametric analyses are conducted to evaluate the influence of nozzle contour, area ratio, and throat geometry on flow acceleration and thrust coefficient. The results demonstrate close agreement with theoretical predictions of isentropic compressible flow while also highlighting deviations due to viscous and three-dimensional effects. These findings provide design insights for optimizing nozzle performance across propulsion applications, from launch vehicles to high-speed air-breathing systems. We obtained absolute error differences of 2.05 percent, 6.03 percent, and 9.9 percent in the throat temperature measurements for the RL10B2, SSME-40k, and A-1 nozzles, respectively. - oai:arXiv.org:2510.11667v3 + The study of coherent Rayleigh-Brillouin scattering in multiple flow regimes using unified gas-kinetic scheme + https://arxiv.org/abs/2512.15357 + arXiv:2512.15357v2 Announce Type: replace +Abstract: Coherent Rayleigh-Brillouin scattering (CRBS) holds great promise for the characterization of gas properties and the investigation of gas kinetic processes. The CRBS spectrum exhibits a strong dependence on the Knudsen number (Kn), revealing its inherently multiscale nature. In the unified gas-kinetic scheme (UGKS), collisions are intrinsically coupled with free transport during flux construction, endowing the method with distinct multiscale capabilities. Specifically, the UGKS reduces to a Boltzmann solver when the relaxation time is greater than or equal to the time step, and to the gas-kinetic scheme (GKS)-a Navier-Stokes solver-when the relaxation time is much smaller than the time step, thereby accommodating flow regimes without constraints on the molecular mean free path or collision time. In this study, the UGKS is extended to simulate CRBS phenomena, with the governing equation formulated based on the BGK-Shakhov model. Detailed derivations are provided. To account for the additional perturbation source term, a second-order accurate numerical algorithm is developed using the Strang splitting method within the UGKS framework. The proposed model is validated against argon CRBS experiments, demonstrating excellent agreement. Building on this validated framework, the impact of incident signal intensity on CRBS spectra across a range of Knudsen numbers is systematically examined, accompanied by an in-depth analysis of the underlying physical mechanisms. This work broadens the applicability of CFD-based CRBS simulations and provides a reliable numerical foundation for exploring high-intensity, multiscale gas-kinetic phenomena in future research. + oai:arXiv.org:2512.15357v2 physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by/4.0/ - Noah L. Estrada, Marc A. Cantu, Arturo Rodriguez, Andrew R. Ybarra, Jeffrey H. Farris, Francisco O. Aguirre Ortega, Vineeth Vijaya Kumar, Vinod Kumar + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Xiaozhe Xi, Junzhe Cao, Kun Xu - Design optimization of silicon nitride nanomechanical resonators for thermal infrared detectors: a guide through key figures of merit - https://arxiv.org/abs/2510.14758 - arXiv:2510.14758v2 Announce Type: replace -Abstract: Thermomechanical infrared (IR) detectors have emerged as promising alternatives to traditional photon and thermoelectric sensors, offering broadband sensitivity and low noise without the need for cryogenic cooling. Despite recent advances, the field still lacks a unified framework to guide the design of these nanomechanical systems. This work addresses that gap by providing a comprehensive design guide for IR thermal detectors based on silicon nitride drumhead and trampolines. Leveraging a validated analytical model, we systematically explore how geometry, tensile stress, and optical properties influence key performance metrics such as thermal time constant, noise-equivalent power, and specific detectivity. The analysis encompasses both bare silicon nitride and structures with broadband absorber layers, revealing how different parameter regimes affect the trade-off between sensitivity and response speed. Rather than focusing on a single device architecture, this study maps out a broad design space, enabling performance prediction and optimisation for a variety of application requirements. As such, it serves not only as a reference for benchmarking existing devices but also as a practical tool for engineering next-generation IR sensors that can operate close to the fundamental detection limit. This work is intended as a foundational resource for researchers and designers aiming to tailor IR detectors to specific use cases. - oai:arXiv.org:2510.14758v2 - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 + Full-Wave Optical Modeling of Leaf Internal Light Scattering Dynamics with Potential Applications for Early Detection of Foliar Fungal Disease + https://arxiv.org/abs/2512.17132 + arXiv:2512.17132v2 Announce Type: replace +Abstract: Light interacting with plant leaves undergoes reflection, transmission, scattering, and absorption, which together determine leaf optical properties. Changes in leaf architecture disrupt internal light scattering dynamics and consequently affect photosynthetic performance. Previous studies on internal leaf light scattering have primarily relied on ray-tracing approaches (e.g., Raytran) or radiative-transfer models (e.g., PROSPECT). However, these high-frequency approximations cannot capture diffraction and coherent multiple scattering in wavelength-scale leaf tissues, unlike full-wave electromagnetic simulations. Here, we employ GPU-accelerated Finite-Difference Time-Domain (FDTD) simulations to model internal light scattering dynamics using segmented cross-section image geometries of representative dicot and monocot leaves with wavelength-dependent complex refractive indices. The simulations accurately reproduce the reflectance and transmittance characteristics of healthy leaves, showing strong agreement with the PROSPECT model, with average Lin's concordance values of 0.8962 for dicot leaves and 0.7849 for monocot leaves. We further simulate early-stage necrotrophic fungal infection by modeling melanized hyphae penetrating the cuticle and upper epidermis. Diseased leaves exhibit a pronounced reduction in visible green reflectance and a marked suppression of the near-infrared reflectance plateau, consistent with experimental observations. Remaining discrepancies in the visible band are expected to be reduced through more advanced geometric and material modeling. This proof-of-concept study presents a full-wave FDTD optical modeling framework for plant-leaf light scattering, enabling physics-based analysis of internal scattering before and after early-stage fungal penetration and supporting the use of light scattering as an indicator for pre-symptomatic plant fungal disease detection. + oai:arXiv.org:2512.17132v2 + physics.bio-ph + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Paolo Martini, Kostas Kanellopulos, Silvan Schmid + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Da-Young Lee, Dong-Yeop Na - Herman-Kluk-Like Semi-Classical Initial-Value Representation for Boltzmann Operator - https://arxiv.org/abs/2510.14761 - arXiv:2510.14761v2 Announce Type: replace -Abstract: The coherent-state initial-value representation (IVR) for the semi-classical real-time propagator of a quantum system, developed by Herman and Kluk (HK), is widely used in computational studies of chemical dynamics. On the other hand, the Boltzmann operator $e^{-\hat{H}/(k_B T)}$, with $\hat{H}$,$k_B$, and $T$ representing the Hamiltonian, Boltzmann constant, and temperature, respectively, plays a crucial role in chemical physics and other branches of quantum physics. One might naturally assume that a semi-classical IVR for the matrix element of this operator in the coordinate representation (i.e., $ \langle \tilde{x} | e^{-\hat{H}/(k_B T)} | x \rangle$, or the imaginary-time propagator) could be derived via a straightforward ``real-time $\rightarrow$ imaginary-time transformation'' from the HK IVR of the real-time propagator. However, this is not the case, as such a transformation results in a divergence in the high-temperature limit $(T \rightarrow \infty)$. In this work, we solve this problem and develop a reasonable HK-like semi-classical IVR for $ \langle \tilde{x} | e^{-\hat{H}/(k_B T)} | x \rangle$ specifically for systems where either the gradient of the potential energy (i.e., the force intensity) has a finite upper bound, or the potential becomes harmonic in the long-range limit. The integrand in this IVR is a real Gaussian function of the positions $x$ and $\tilde{x}$, which facilitates its application to realistic problems. Our HK-like IVR is exact for free particles and harmonic oscillators, and its effectiveness for other systems is demonstrated through numerical examples. - oai:arXiv.org:2510.14761v2 + Fast, systematic and robust relative binding free energies for simple and complex transformations : dual-LAO + https://arxiv.org/abs/2512.17624 + arXiv:2512.17624v2 Announce Type: replace +Abstract: Relative Binding Free Energy (RBFE) calculations are a cornerstone of rational hit-to-lead and lead optimization in modern drug discovery. However, the high computational cost and limited reliability in tackling large or complex molecular transformations often prevent their routine, high-throughput use. Here we introduce dual-LAO, a novel, highly efficient method for calculating RBFE. Building on the Lambda-ABF-OPES framework, this method combines a dual-topology setup and suitable restraints to dramatically accelerate free energy convergence. We demonstrate that dual-LAO, in combination with the AMOEBA polarizable force field, achieves an unprecedented acceleration factor of 15 to 30 times compared to current state-of-the-art methods on standard drug targets. Crucially, the approach maintains high accuracy and successfully tackles previously prohibitive molecular changes, including scaffold-hopping, buried water displacement, charge changes, ring-opening, and binding pose perturbations. This significant leap in efficiency allows for the widespread, routine integration of predictive molecular simulations into the rapid optimization cycles of drug discovery, enabling chemists to confidently model historically challenging systems in timescales compatible with real-world project deadlines. + oai:arXiv.org:2512.17624v2 physics.chem-ph - quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Binhao Wang, Fan Yang, Chen Xu, Peng Zhang + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Narjes Ansari, F\'elix Aviat, J\'er\^ome H\'enin, Jean-Philip Piquemal, Louis Lagard\`ere - Genesis of a horizontal electric field within the lipid bilayer core and its role in channel gating - https://arxiv.org/abs/2510.15637 - arXiv:2510.15637v4 Announce Type: replace -Abstract: For over a century, the electric field of biological membranes has been regarded as a one-dimensional quantity, defined solely by the component normal to the bilayer (E_VERT). Here, we challenge this conventional view by developing a device that generates a horizontal electric field within the hydrophobic core of a lipid bilayer (E_HORZ). The device incorporates micrometer-scale electrodes embedded within the bilayer's torus, enabling the steady generation of E_HORZ. Applied E_HORZ selectively and reversibly accelerates the slow inactivation of a voltage-gated potassium channel, while leaving activation essentially unchanged. Physical considerations reveal that E_HORZ naturally arises wherever membrane potential varies spatially, such as at the wavefront of an action potential, implying that it is inherent to many physiological processes. This E_HORZ system provides experimental access to fully three-dimensional membrane electric fields, revealing previously overlooked dimension of membrane bioelectricity. - oai:arXiv.org:2510.15637v4 - physics.bio-ph - Mon, 22 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Maki Komiya, Madoka Sato, Teng Ma, Hironori Kageyama, Tatsuya Nomoto, Takahisa Maki, Masayuki Iwamoto, Miyu Terashima, Daiki Ando, Takaya Watanabe, Yoshikazu Shimada, Daisuke Tadaki, Hideaki Yamamoto, Yuzuru Tozawa, Ryugo Tero, Albert Marti, Jordi Madrenas, Shigeru Kubota, Fumihiko Hirose, Michio Niwano, Shigetoshi Oiki, Ayumi Hirano-Iwata + Understanding the Lithium Ion Transport in Concentrated Block-Copolymer Electrolytes on a Microscopic Level + https://arxiv.org/abs/2010.11673 + arXiv:2010.11673v3 Announce Type: replace-cross +Abstract: Block-copolymer electrolytes with lamellar microstructure show promising results regarding the ion transport in experiments. Motivated by these observations we study block-copolymers consisting of a polystyrene (PS) block and a poly(ethylene oxide) (PEO) block which were assembled in a lamellar structure. The lamella was doped with various amounts of lithium-bis(trifluoromethane)sulfonimide (LiTFSI) until very high loadings with ratios of EO monomers to cations up to 1:1 were reached. We present insights into the structure and ion transport from extensive Molecular Dynamics simulations. For high salt concentrations most cations are not coordinated by PEO but rather by TFSI and THF. More specifically, LiTFSI partially separates from the PEO domain and forms a network-like structure in the middle of the lamella. This central salt-rich layer plays a decisive role to enable remarkably good cationic mobilities as well as high transport numbers in agreement with the experimental results. + oai:arXiv.org:2010.11673v3 + cond-mat.soft + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Len Kimms, Diddo Diddens, Andreas Heuer - All-Optical Photonic Crystal Bolometer with Ultra-Low Heat Capacity for Scalable Thermal Imaging - https://arxiv.org/abs/2511.22006 - arXiv:2511.22006v2 Announce Type: replace -Abstract: High-speed thermal imaging in the long-wave infrared (LWIR) is critical for applications from autonomous navigation to medical screening, yet existing uncooled detectors are fundamentally constrained. Resistive bolometers are limited by electronic noise and the parasitic thermal load of wired readouts, while state-of-the-art nanomechanical resonators typically rely on vacuum packaging to maintain the mechanical $Q$ needed for sensitivity. Here, we introduce and demonstrate an uncooled thermal detector that addresses these challenges via an all-optical transduction mechanism. The heterogeneously integrated pixel is engineered for minimal thermal mass, combining pyrolytic carbon absorbers for broadband LWIR absorption, hollow zirconia structures for ultra-low-conductance thermal isolation, and a silicon photonic crystal cavity that serves as a high-$Q$ optical thermometer. Operating at ambient temperature and pressure, we measure a specific detectivity of $1.1\times10^{7}$ Jones and a thermal time constant of $27~\mu \mathrm{s}$, corresponding to a speed that surpasses typical high-sensitivity uncooled technologies by an order of magnitude. Based on this detectivity measurement, which is limited by the noise floor of the external optical detection electronics, a physics-based model predicts a $>25\text{-fold}$ performance enhancement to its fundamental thermorefractive-noise-limited value ($3\times10^{8}$ Jones). The optical readout remains functional across ambient and vacuum environments. We expect this architecture to provide a general route toward scalable, high-performance thermal imaging systems. - oai:arXiv.org:2511.22006v2 + Orientation disparity in GaN/graphene/$m$-sapphire: control-based re-examination of thru-hole epitaxy + https://arxiv.org/abs/2308.15779 + arXiv:2308.15779v2 Announce Type: replace-cross +Abstract: The crystallographic orientation of films grown on 2D-masked substrates is often used to infer the pathway among remote, van der Waals, and thru-hole (pinhole-seeded) epitaxy. However, attribution of a specific growth mechanism based on orientation can be ambiguous unless mask continuity and substrate pre-treatment are evaluated within a single process window. We compare GaN grown under identical conditions on four m-plane sapphire templates: (i) bare, (ii) "graphene-grown" (high-temperature Ar/H2 with CH4 on), (iii) "anneal-only" (high-temperature Ar/H2 with CH4 off), and (iv) graphene oxide spin-coated and reduced on pristine sapphire. GaN selects (103) on graphene-grown and anneal-only m-plane sapphire, selects (100) on bare m-plane sapphire, and is predominantly (100) with a minority (103) on graphene oxide spin-coated and reduced/pristine m-plane sapphire. High-resolution TEM shows that, on partly graphene-covered samples, nucleation occurs on exposed sapphire (thru-hole), not on graphene, providing mechanism evidence independent of orientation. Within this window, the substrate surface state set by high-temperature Ar/H2 pre-treatment (rather than mask continuity) primarily governs orientation, while open-area effects can play a secondary role. Thus, preferred orientation alone may not determine the growth mechanism; mask continuity and substrate pre-treatment must be explicitly controlled when using orientation as evidence for mechanism assignment. + oai:arXiv.org:2308.15779v2 + cond-mat.mtrl-sci physics.app-ph - physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 - replace - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Louis Follet, Jordan Goldstein, Christopher L. Panuski, Ian Christen, Sivan Trajtenberg-Mills, Dirk R. Englund + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Su Young An, Hyunkyu Lee, Gunhoon Beak, Hyeonoh Jo, Jae Hun Kim, Jongwoo Ha, Jieun Yang, Changwook Dong, Jaewu Choi, Joonwon Lim, Chinkyo Kim - Debt, Growth, and the Carbon Lock-In - https://arxiv.org/abs/2512.05063 - arXiv:2512.05063v2 Announce Type: replace -Abstract: Despite decades of climate policy and rapid improvements in energy efficiency, global CO2 emissions continue to rise, suggesting the presence of structural drivers that offset efficiency gains. Here we identify financial leverage as a key mechanism underpinning this persistent overshoot. We develop a stochastic macro-financial model linking credit dynamics, economic growth, bankruptcy risk, and cumulative carbon emissions. The model shows that debt-financed growth systematically amplifies cumulative emissions, locking economies into high-carbon trajectories even as emissions intensity declines. This arises from a double constraint: debt repayment requires sustained growth, while growth remains energy-dependent and thus generates emissions. When growth becomes increasingly dependent on leverage, financial instability and cumulative emissions rise, while gains in real wealth diminish, revealing a leverage frontier beyond which additional credit primarily generates risk. Calibrating the model to multi-decade data for the US, China, France and Denmark, we find a robust coupling between debt accumulation, cumulative GDP and cumulative emissions across distinct economic structures. These results indicate that achieving net-zero targets requires aligning credit allocation with decarbonisation objectives - oai:arXiv.org:2512.05063v2 - physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by/4.0/ - Silvia Montagnania, Barnabe Ledoux, David Lacoste + Towards Arbitrary Time-frequency Mode Squeezing with Self-conjugated Mode Squeezing in Fiber + https://arxiv.org/abs/2406.19991 + arXiv:2406.19991v2 Announce Type: replace-cross +Abstract: Optical parametric amplification generates squeezed light in device-specific sets of time-frequency eigenmodes, and it has been widely accepted that detection and utilization of squeezing must comply with this modal constraint. We show that this constraint can be considerably relaxed under the continuous-wave pump and broadband phase-matching approximation, where the modal decomposition is non-unique. Specifically, any time-frequency mode with "self-conjugated" spectral symmetry can approximate a squeezing eigenmode, and partial homodyne detection can herald squeezing in arbitrary time-frequency modes. We demonstrate this using a high-efficiency, low-loss all-fiber source, measuring 4.38 +- 0.11dB and 0.88 +- 0.09 dB squeezing on partially coherent and chaotic self-conjugated modes. Using a bichromatic self-conjugated mode with reduced local-oscillator noise, we achieve 7.50 +- 0.12dB squeezing, which represents the highest level reported for fully guided-wave squeezing sources based on chi(2) and chi(3) nonlinearities. + oai:arXiv.org:2406.19991v2 + quant-ph + physics.optics + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + Han Liu, Meng Lon Iu, Noor Hamdash, Amr S. Helmy - Bayesian Optimization of Laser-Wakefield Acceleration via Spectral Pulse Shaping - https://arxiv.org/abs/2512.09125 - arXiv:2512.09125v2 Announce Type: replace -Abstract: In this paper, we investigate the effect of spectral pulse shaping of the laser driver on the performance of channel-guided, laser-plasma accelerators. The study was carried out with the assistance of Bayesian optimization using particle-in-cell simulations. We used a realistic plasma profile based on a novel optical-field-ionized channel technique with ionization injection and low on-axis plasma densities to maximize the energy gain of the electron bunch trailing the laser. Spectral shaping allows us to modify the temporal profile of the laser driver while keeping the laser energy constant, affecting the acceleration and injection processes. Given the complexity and breadth of the parameter space in question, we used numerical optimization to identify high performers. In particular, we found laser profiles with additional spectral content that, when used with optimal plasma channel parameters, result in charge content an order of magnitude higher than the baseline Gaussian case while also increasing the mean energy of the electron bunch. - oai:arXiv.org:2512.09125v2 + Observation of quantum effects on radiation reaction in strong fields + https://arxiv.org/abs/2407.12071 + arXiv:2407.12071v3 Announce Type: replace-cross +Abstract: Radiation reaction, the force experienced by an accelerated charge due to radiation emission, has long been the subject of extensive theoretical and experimental research. Experimental verification of a quantum, strong-field description of radiation reaction is fundamentally important, and has wide-ranging implications for astrophysics, laser-driven particle acceleration, next-generation particle colliders and inverse-Compton photon sources for medical and industrial applications. However, the difficulty of accessing regimes where strong field and quantum effects dominate inhibited previous efforts to observe quantum radiation reaction in charged particle dynamics with high significance. We report the first high significance (> 5{\sigma}) observation of strong-field radiation reaction on electron spectra where quantum effects are substantial. We obtain the first, quantitative, strong evidence favouring the quantum-continuous and quantum-stochastic models over the classical model; the quantum models perform comparably. The lower electron energy losses predicted by the quantum models accounts for their improved performance. Model comparison was performed using a novel Bayesian framework which has widespread utility for laser-particle collision experiments, including those utilising conventional accelerators, where some collision parameters cannot be measured directly. + oai:arXiv.org:2407.12071v3 + hep-ph physics.plasm-ph - math.OC - physics.acc-ph - Mon, 22 Dec 2025 00:00:00 -0500 - replace + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross http://creativecommons.org/licenses/by/4.0/ - B. Z. Djordjevi\'c, C. Benedetti, A. D. McNaughton, R. Lehe, H. -E. Tsai, S. C. Wilks, B. A. Reagan, G. J. Williams, J. van Tilborg, C. B. Schroeder + Eva E. Los, Elias Gerstmayr, Christopher Arran, Matthew J. V. Streeter, Cary Colgan, Claudia C. Cobo, Brendan Kettle, Thomas G. Blackburn, Nicolas Bourgeois, Luke Calvin, Jason Cardarelli, Niall Cavanagh, Stephen J. D. Dann, Antonino Di Piazza, Rebecca Fitzgarrald, Anton Ilderton, Christoph H. Keitel, Mattias Marklund, Paul McKenna, Christopher D. Murphy, Zulfikar Najmudin, Peter Parsons, Paramel P. Rajeev, Daniel R. Symes, Matteo Tamburini, Alexander G. R. Thomas, Jonathan C. Wood, Matthew Zepf, Gianluca Sarri, Christopher P. Ridgers, Stuart P. D Mangles - A nanopore-gated sub-attoliter silicon nanocavity for single-molecule trapping and analysis - https://arxiv.org/abs/2512.13179 - arXiv:2512.13179v2 Announce Type: replace -Abstract: Biomolecules exhibit dynamic conformations critical to their functions, yet observing these processes at the single-molecule level under native conditions remains a formidable challenge. While surface immobilization has been widely used to extend observation times, it could disrupt molecular dynamics and impede biological function. Moreover, the study of weak molecular interactions requires high local concentrations, often leading to problems with signal saturation in fluorescence-based approaches. Recent advancements in single-molecule trapping techniques have addressed some limitations, but achieving precise, controllable, long-term trapping in a molecularly crowded environment without external forces remains difficult. Here, we introduce a nanopore-gated sub-attoliter silicon nanocavity that enables precise, non-perturbative trapping of individual biomolecules for extended observation times, eliminating the need for external forces. Using nucleosomes as model systems, we demonstrate single-molecule F\"orster resonance energy transfer (smFRET) to monitor relative distances. Our data also show that an applied electric field can modulate the conformational properties of macromolecules, emphasizing a key advantage of our device: it does not require an electric field to retain trapped molecules. We envision this nanocavity platform as a powerful tool for interrogating molecular dynamics in physiologically relevant environments, offering unperturbed access to weak and transient interactions that are central to biological regulation. - oai:arXiv.org:2512.13179v2 - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 - replace - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Funing Liu, Qitao Hu, Anton Sabantsev, Giovanni Di Muccio, Shuangshuang Zeng, Mauro Chinappi, Sebastian Deindl, Zhen Zhang + A dual approach to proving electoral fraud using statistics and forensic evidence (Dvojnoe dokazatel'stvo falsifikazij na vyborah statistikoj i kriminalistikoj) + https://arxiv.org/abs/2412.04535 + arXiv:2412.04535v3 Announce Type: replace-cross +Abstract: Electoral fraud often manifests itself as statistical anomalies in election results, yet its extent can rarely be reliably confirmed by other evidence. Here we report the complete results of municipal elections in the town of Vlasikha near Moscow, where we observe both statistical irregularities in the vote-counting transcripts and forensic evidence of tampering with ballots during their overnight storage. We evaluate two types of statistical signatures in the vote sequence that can prove batches of fraudulent ballots have been injected. We find that pairs of factory-made security bags with identical serial numbers are used in this fraud scheme. At 8 out of our 9 polling stations, the statistical and forensic evidence agrees (identifying 7 as fraudulent and 1 as honest), while at the remaining station the statistical evidence detects the fraud while the forensic one is insufficient. We also illustrate that the use of tamper-indicating seals at elections is inherently unreliable. + oai:arXiv.org:2412.04535v3 + stat.AP + physics.soc-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-sa/4.0/ + Elect. Polit. 14, issue 2, 4 (2025); https://electoralpolitics.org/en/articles/dvoinoe-dokazatelstvo-falsifikatsii-na-vyborakh-statistikoi-i-kriminalistikoi/ + Andrey Podlazov, Vadim Makarov - Multiscale modeling of blood circulation with cerebral autoregulation and network pathway analysis for hemodynamic redistribution in the vascular network with anatomical variations and stenosis conditions - https://arxiv.org/abs/2512.15482 - arXiv:2512.15482v2 Announce Type: replace -Abstract: Cerebral hemodynamics is fundamentally regulated by the Circle of Willis (CoW), which redistributes flow through communicating arteries to stabilize perfusion under anatomical variations and vascular stenosis. In this study, we develop a multiscale circulation model by coupling a systemic hemodynamic framework with a cerebral arterial network reconstructed from medical imaging. The model incorporates a cerebral autoregulation mechanism (CAM) and enables quantitative simulation of flow redistribution within the CoW under normal, anatomically varied, and stenotic conditions. Baseline simulations reproduce physiological flow distributions in which communicating arteries remain nearly inactive, showing negligible cross-flow and agreement with clinical measurements. In contrast, anatomical variations reveal distinct collateral activation patterns: the anterior communicating artery (ACoA) emerges as the earliest and most sensitive functional collateral, whereas the posterior communicating arteries (PCoAs) exhibit structure-dependent engagement. Progressive stenosis simulations further demonstrate a transition from a complete CoW to a fetal-type posterior cerebral artery (PCA) configuration, characterized by early ACoA flow reversal followed by ipsilateral PCoA activation, consistent with experimental and transcranial Doppler observations. Finally, a path-based quantitative analysis is introduced to illustrate how the cerebral vascular network dynamically reconfigures collateral pathways in response to structural changes. Overall, the proposed framework provides a physiologically interpretable, image-informed tool for investigating cerebral flow regulation through functional collaterals within the CoW, with potential applications in the diagnosis and treatment planning of cerebrovascular diseases. - oai:arXiv.org:2512.15482v2 - physics.med-ph - cs.NA - math.NA - Mon, 22 Dec 2025 00:00:00 -0500 - replace + Slow spatial migration can help eradicate cooperative antimicrobial resistance in time-varying environments + https://arxiv.org/abs/2501.01939 + arXiv:2501.01939v2 Announce Type: replace-cross +Abstract: Antimicrobial resistance (AMR) is a global threat and combating its spread is of paramount importance. AMR often results from a cooperative behaviour with shared drug protection. Microbial communities generally evolve in volatile, spatially structured settings. Migration, space, fluctuations, and environmental variability all have a significant impact on the development and proliferation of AMR. While drug resistance is enhanced by migration in static conditions, this changes in time-fluctuating spatially structured environments. Here, we consider a two-dimensional metapopulation consisting of demes in which drug-resistant and sensitive cells evolve in a time-changing environment. This contains a toxin against which protection can be shared (cooperative AMR). Cells migrate between demes and connect them. When the environment and the deme composition vary on the same timescale, strong population bottlenecks cause fluctuation-driven extinction events, countered by migration. We investigate the influence of migration and environmental variability on the AMR eco-evolutionary dynamics by asking at what migration rate fluctuations can help clear resistance and what are the near-optimal environmental conditions ensuring the quasi-certain eradication of resistance in the shortest possible time. By combining analytical and computational tools, we answer these questions by determining when the resistant strain goes extinct across the entire metapopulation. While dispersal generally promotes strain coexistence, here we show that slow-but-nonzero migration can speed up and enhance resistance clearance, and determine the near-optimal conditions for this phenomenon. We discuss the impact of our findings on laboratory-controlled experiments and outline their generalisation to lattices of any spatial dimension. + oai:arXiv.org:2501.01939v2 + q-bio.PE + cond-mat.stat-mech + nlin.AO + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross http://creativecommons.org/licenses/by/4.0/ - Jiawei Liu, Atsushi Kanoke, Hidenori Endo, Kuniyasu Niizuma, Hiroshi Suito + 10.1101/2024.12.30.630406 + Llu\'is Hern\'andez-Navarro, Kenneth Distefano, Uwe C. T\"auber, Mauro Mobilia - The Quantum Rashomon Effect: A Strengthened Frauchiger-Renner Argument - https://arxiv.org/abs/2011.12716 - arXiv:2011.12716v5 Announce Type: replace-cross -Abstract: The Frauchiger-Renner argument aims to show that `quantum theory cannot consistently describe the use of itself': in many-party settings where agents are themselves subject to quantum experiments, agents may make predictions that contradict observations. Here, we introduce a simplified setting using only three agents, that is independent of the initial quantum state, thus eliminating in particular any need for entanglement, and furthermore does not need to invoke any final measurement and resulting collapse. Nevertheless, the predictions and observations made by the agents cannot be integrated into a single, consistent account. We propose that the existence of this sort of \emph{Rashomon effect}, i.e. the impossibility of uniting different perspectives, is due to failing to account for the limits put on the information available about any given system as encapsulated in the notion of an \emph{epistemic horizon}. - oai:arXiv.org:2011.12716v5 - quant-ph - physics.hist-ph - Mon, 22 Dec 2025 00:00:00 -0500 + On the Role of Chapman's Hydrostatic Solar Wind Mechanism in Parker's Hydrodynamic Solar Wind Model + https://arxiv.org/abs/2501.02731 + arXiv:2501.02731v2 Announce Type: replace-cross +Abstract: The global role of Chapman's hydrostatic solar wind mechanism in Parker's hydrodynamic solar wind model is investigated by using the de Laval nozzle analogy for the generation of flow acceleration in the latter model. The action of solar gravity in Parker's hydrodynamic solar wind model is shown to be geometrically equivalent to a renormalization of the actual wind channel area via a multiplicative factor, which is precisely Chapman's hydrostatic density profile. So, Chapman's hydrostatic solar wind mechanism appears to continue to be operative, on a global level (not just locally near the coronal base), in Parker's hydrodynamic solar wind model, the effects of solar gravity in Parker's hydrodynamic model being essentially encapsulated by Chapman's hydrostatic model. This result is shown to be robust by considering both isothermal gas and polytropic gas models as well as an n-dimensional (n= 1, 2, 3) underlying space for the solar wind. + oai:arXiv.org:2501.02731v2 + astro-ph.SR + physics.plasm-ph + physics.space-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Jochen Szangolies + Bhimsen Shivamoggi - HGQ: High Granularity Quantization for Real-time Neural Networks on FPGAs - https://arxiv.org/abs/2405.00645 - arXiv:2405.00645v3 Announce Type: replace-cross -Abstract: Neural networks with sub-microsecond inference latency are required by many critical applications. Targeting such applications deployed on FPGAs, we present High Granularity Quantization (HGQ), a quantization-aware training framework that optimizes parameter bit-widths through gradient descent. Unlike conventional methods, HGQ determines the optimal bit-width for each parameter independently, making it suitable for hardware platforms supporting heterogeneous arbitrary precision arithmetic. In our experiments, HGQ shows superior performance compared to existing network compression methods, achieving orders of magnitude reduction in resource consumption and latency while maintaining the accuracy on several benchmark tasks. These improvements enable the deployment of complex models previously infeasible due to resource or latency constraints. HGQ is open-source and is used for developing next-generation trigger systems at the CERN ATLAS and CMS experiments for particle physics, enabling the use of advanced machine learning models for real-time data selection with sub-microsecond latency. - oai:arXiv.org:2405.00645v3 - cs.LG - physics.ins-det - Mon, 22 Dec 2025 00:00:00 -0500 + Witnessing non-stationary and non-Markovian environments with a quantum sensor + https://arxiv.org/abs/2501.05814 + arXiv:2501.05814v2 Announce Type: replace-cross +Abstract: Quantum sensors offer exceptional sensitivity to nanoscale magnetic fluctuations, where non-stationary effects -- such as spin diffusion -- and non-Markovian dynamics arising from coupling to few environmental degrees of freedom play critical roles. Because fully reconstructing the microscopic structure of realistic spin baths is often infeasible, a practical challenge is to identify the dynamical features that are actually encoded in the sensor's decoherence signal. Here, we demonstrate how quantum sensors can operationally characterize the statistical nature of environmental noise, distinguishing between stationary and non-stationary behaviors, as well as Markovian and non-Markovian dynamics. Using nitrogen-vacancy (NV) centers in diamond as a platform, we develop a physical noise model that captures the essential dynamical features of realistic environments relevant to sensor observables -- independently of the microscopic bath details -- and provides analytical predictions for Ramsey decay across different regimes. These predictions are experimentally validated through controlled noise injection with tunable correlation properties. Our results showcase the capability of quantum sensors to isolate and identify key dynamical properties of complex environments, without requiring full microscopic bath reconstruction. This work clarifies the operational signatures of non-stationarity and non-Markovian behavior at the nanoscale and lays the foundation for strategies that mitigates decoherence while exploiting environmental dynamics for enhanced quantum sensing. + oai:arXiv.org:2501.05814v2 + quant-ph + cond-mat.mes-hall + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-nd/4.0/ + 10.1103/13mr-493z + John W. Rosenberg, Mart\'in Kuffer, Inbar Zohar, Rainer St\"ohr, Andrej Denisenko, Analia Zwick, Gonzalo A. \'Alvarez, Amit Finkler + + + Dielectrocapillarity for exquisite control of fluids + https://arxiv.org/abs/2503.09855 + arXiv:2503.09855v2 Announce Type: replace-cross +Abstract: Spatially varying electric fields are prevalent throughout nature, such as in nanoporous materials and biological membranes, and technology, e.g, patterned electrodes and van der Waals heterostructures. While uniform fields cause free ions to migrate, for polar fluids they simply reorient the constituent molecules. In contrast, electric field gradients (EFGs) induce a dielectrophoretic force, offering fine control of polar fluids even in the absence of free charges. Despite their vast potential for optimizing fluid behavior under confinement, such as in nanoporous electrodes, nanofluidic devices, and chemical separation materials. EFGs remain largely unexplored at the microscopic level due to the absence of a rigorous first-principles theory of electrostriction. By integrating state-of-the-art advances in liquid state theory and deep learning, we reveal how EFGs modulate fluid structure and capillarity. We demonstrate that dielectrophoretic coupling enables tunable control over the liquid-gas phase transition, capillary condensation, and fluid uptake into porous media. Our findings establish "dielectrocapillarity" -- the use of EFGs to manipulate confined fluids -- as a powerful mechanism for controlling volumetric capacity in nanopores, holding immense potential for energy storage, selective gas separation, and tunable hysteresis in neuromorphic nanofluidics. Furthermore, by linking nanoscale dielectrocapillarity to macroscopic dielectrowetting, we establish a foundation for field-controlled wetting and adsorption phenomena of polar fluids across length scales. + oai:arXiv.org:2503.09855v2 + cond-mat.soft + cond-mat.mes-hall + cond-mat.mtrl-sci + cond-mat.stat-mech + physics.chem-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - 10.1145/3748173.3779200 - Chang Sun, Zhiqiang Que, Thea K. {\AA}rrestad, Vladimir Loncar, Jennifer Ngadiuba, Wayne Luk, Maria Spiropulu + Anna T. Bui, Stephen J. Cox - The long way of a viscous vortex dipole - https://arxiv.org/abs/2407.13562 - arXiv:2407.13562v2 Announce Type: replace-cross -Abstract: We consider the evolution of a viscous vortex dipole in $R^2$ originating from a pair of point vortices with opposite circulations. At high Reynolds number $Re >> 1$, the dipole can travel a very long way, compared to the distance between the vortex centers, before being slowed down and eventually destroyed by diffusion. In this regime we construct an accurate approximation of the solution in the form of a two-parameter asymptotic expansion involving the aspect ratio of the dipole and the inverse Reynolds number. We then show that the exact solution of the Navier-Stokes equations remains close to the approximation on a time interval of length $O(Re^\sigma)$, where $\sigma < 1$ is arbitrary. This improves upon previous results which were essentially restricted to $\sigma = 0$. As an application, we provide a rigorous justification of an existing formula which gives the leading order correction to the translation speed of the dipole due to finite size effects. - oai:arXiv.org:2407.13562v2 - math.AP - physics.flu-dyn - Mon, 22 Dec 2025 00:00:00 -0500 + Density estimation via mixture discrepancy and moments + https://arxiv.org/abs/2504.01570 + arXiv:2504.01570v2 Announce Type: replace-cross +Abstract: With the aim of generalizing histogram statistics to higher dimensional cases, density estimation via discrepancy based sequential partition (DSP) has been proposed to learn an adaptive piecewise constant approximation defined on a binary sequential partition of the underlying domain, where the star discrepancy is adopted to measure the uniformity of particle distribution. However, the calculation of the star discrepancy is NP-hard and it does not satisfy the reflection invariance and rotation invariance either. To this end, we use the mixture discrepancy and the comparison of moments as a replacement of the star discrepancy, leading to the density estimation via mixture discrepancy based sequential partition (DSP-mix) and density estimation via moment-based sequential partition (MSP), respectively. Both DSP-mix and MSP are computationally tractable and exhibit the reflection and rotation invariance. Numerical experiments in reconstructing Beta mixtures, Gaussian mixtures and heavy-tailed Cauchy mixtures up to 30 dimension are conducted, demonstrating that MSP can maintain the same accuracy compared with DSP, while gaining an increase in speed by a factor of two to twenty for large sample size, and DSP-mix can achieve satisfactory accuracy and boost the efficiency in low-dimensional tests ($d \le 6$), but might lose accuracy in high-dimensional problems due to a reduction in partition level. + oai:arXiv.org:2504.01570v2 + stat.ML + cs.LG + physics.comp-ph + stat.ME + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Michele Dolce, Thierry Gallay + Zhengyang Lei, Lirong Qu, Sihong Shao, Yunfeng Xiong - Deriving the Born Rule from a model of the quantum measurement process - https://arxiv.org/abs/2408.06375 - arXiv:2408.06375v4 Announce Type: replace-cross -Abstract: The quantum mechanics postulate called the Born Rule attributes a probabilistic meaning to a wave function. This paper derives the Born Rule from other quantum principles along with a model of the measurement process. - The nondeterministic nature of quantum measurements is hypothesized to arise from an ignorance of the quantum states of a measuring device's microscopic components. Their interactions with a system to be measured are modeled heuristically with any member of a particular class of stochastic processes, each of which generate the Born Rule. One member of the class appears particularly compatible with properties expected of quantum interactions. - oai:arXiv.org:2408.06375v4 - quant-ph - physics.hist-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Neutral theory of cooperative dynamics + https://arxiv.org/abs/2506.09737 + arXiv:2506.09737v2 Announce Type: replace-cross +Abstract: Mutualistic interactions are widespread in nature, from plant communities and microbiomes to human organizations. Along with competition for resources, cooperative interactions shape biodiversity and contribute to the robustness of complex ecosystems. We present a stochastic neutral theory of cooperator species. Our model shares with the classic neutral theory of biodiversity the assumption that all species are equivalent, but crucially differs in requiring cooperation between species for replication. With low migration, our model displays a bimodal species-abundance distribution, with a high-abundance mode associated with a core of cooperating species. This core is responsible for maintaining a diverse pool of long-lived species, which are present even at very small migration rates. We derive analytical expressions of the steady-state species abundance distribution, as well as scaling laws for diversity, number of species, and residence times. With high migration, our model recovers the results of classic neutral theory. We briefly discuss implications of our analysis for research on the microbiome, synthetic biology, and the origin of life. + oai:arXiv.org:2506.09737v2 + q-bio.PE + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Alan Schaum + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.1073/pnas.251542312 + PNAS, 122 (51): e2515423122 (2025) + Jordi Pi\~nero, Artemy Kolchinsky, Sidney Redner, Ricard Sol\'e - Quantifying the Dunkelflaute -- An analysis of variable renewable energy droughts in Europe - https://arxiv.org/abs/2410.00244 - arXiv:2410.00244v3 Announce Type: replace-cross -Abstract: Variable renewable energy droughts, also called "Dunkelflaute", emerge as a challenge for climate-neutral energy systems based on variable renewables. Here we characterize European drought events for on- and offshore wind power, solar photovoltaics, and renewable technology portfolios, using 38 historic weather years and an advanced identification method. Their characteristics heavily depend on the chosen drought threshold, questioning the usefulness of single-threshold analyses. Applying a multi-threshold framework, we quantify how the complementarity of wind and solar power temporally and spatially alleviates drought frequency, return periods, duration, and severity within (portfolio effect) and across countries (balancing effect). We identify the most extreme droughts, which drive major discharging periods of long-duration storage in a fully renewable European energy system, based on a policy-relevant decarbonization scenario. Such events comprise sequences of shorter droughts of varying severity. The most extreme event occurred in winter 1996/97 and lasted 55 days in an idealized, perfectly interconnected setting. The average renewable availability during this period was still 47% of its long-run mean. System planners must consider such events when planning for storage and other flexibility technologies. Methodologically, we conclude that using arbitrary single calendar years is not suitable for modeling weather-resilient energy scenarios. - oai:arXiv.org:2410.00244v3 - eess.SY - cs.SY - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Chimera states on m-directed hypergraphs + https://arxiv.org/abs/2506.12511 + arXiv:2506.12511v4 Announce Type: replace-cross +Abstract: Chimera states are synchronization patterns in which coherent and incoherent regions coexist in systems of identical oscillators. This elusive phenomenon has attracted significant interest and has been widely analyzed, revealing several types of dynamical states. Most studies involve reciprocal pairwise couplings, where each oscillator exerts and receives the same interaction from neighboring ones, thus being modeled via symmetric networks. However, real-world systems often exhibit non-reciprocal, non-pairwise (many-body) interactions. Previous studies have shown that chimera states are more elusive in the presence of non-reciprocal pairwise interactions, while they are easier to observe when the interactions are reciprocal and higher-order (many-body). In this work, we investigate the emergence of chimera states on non-reciprocal higher-order structures, called mdirected hypergraphs, which we compare with their corresponding networks, and we observe that chimera state and specifically amplitude-mediated chimeras can emerge due to directionality, which had not been previously observed in the absence of directionality. We also compare the effect of non-reciprocal interactions between higher-order and pairwise couplings, and we find numerically that chimera states appear over a broader parameter range when considering higher-order interactions than in the corresponding network case, demonstrating the impact of directionality and the effect of higher-order interactions. Finally, the nature of phase chimeras has been further validated through phase reduction theory. + oai:arXiv.org:2506.12511v4 + nlin.PS + math-ph + math.MP + nlin.AO + nlin.CD + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Martin Kittel, Wolf-Peter Schill + Rommel Tchinda Djeudjo, Timoteo Carletti, Hiroya Nakao, Riccardo Muolo - An Optimally Accurate Lanczos Algorithm in the Matrix Product State Representation - https://arxiv.org/abs/2504.21786 - arXiv:2504.21786v4 Announce Type: replace-cross -Abstract: We improve the convergence of the Lanczos algorithm using the matrix product state representation. As an alternative to the density matrix renormalization group (DMRG), the Lanczos algorithm avoids local minima and can directly find multiple low-lying eigenstates. However, its performance and accuracy are affected by the truncation required to maintain the efficiency of the tensor network representation. In this work, we propose the modified thick-block Lanczos method to enhance the convergence of the Lanczos algorithm with MPS representation. We benchmark our method on one-dimensional instances of the Fermi-Hubbard model and the Heisenberg model in an external field, using numerical experiments targeting the first five lowest eigenstates. Across these tests, our approach attains the best possible accuracy permitted by the given bond dimension. This work establishes the Lanczos method as a reliable and accurate framework for finding multiple low-lying states within a tensor-network representation - oai:arXiv.org:2504.21786v4 - cond-mat.str-el - physics.comp-ph + Fully Quantum Lattice Gas Automata Building Blocks for Computational Basis State Encodings + https://arxiv.org/abs/2506.12662 + arXiv:2506.12662v3 Announce Type: replace-cross +Abstract: Lattice Gas Automata (LGA) is a classical method for simulating physical phenomena, including Computational Fluid Dynamics (CFD). Quantum LGA (QLGA) is the family of methods that implement LGA schemes on quantum computers. In recent years, QLGA has garnered attention from researchers thanks to its potential of efficiently modeling CFD processes by either reducing memory requirements or providing simultaneous representations of exponentially many LGA states. In this work, we introduce novel building blocks for QLGA algorithms that rely on computational basis state encodings. We address every step of the algorithm, from initial conditions to measurement, and provide detailed complexity analyses that account for all discretization choices of the system under simulation. We introduce multiple ways of instantiating initial conditions, efficient boundary condition implementations for novel geometrical patterns, a novel collision operator that models less restricted interactions than previous implementations, and quantum circuits that extract quantities of interest out of the quantum state. For each building block, we provide intuitive examples and open-source implementations of the underlying quantum circuits. + oai:arXiv.org:2506.12662v3 quant-ph - Mon, 22 Dec 2025 00:00:00 -0500 + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Yu Wang, Zhangyu Yang, Xingyao Wu, Christian B. Mendl + 10.1016/j.jcp.2025.114595 + C\u{a}lin A. Georgescu, Merel A. Schalkers, Matthias M\"oller - How to use score-based diffusion in earth system science: A satellite nowcasting example - https://arxiv.org/abs/2505.10432 - arXiv:2505.10432v2 Announce Type: replace-cross -Abstract: Machine learning (ML) is used for many earth science applications; however, traditional ML methods trained with squared errors often create blurry forecasts. Diffusion models are an emerging generative ML technique with the ability to produce sharper, more realistic images by learning the underlying data distribution. Diffusion models are becoming more prevalent, yet adapting them for earth science applications can be challenging because most articles focus on theoretical aspects of the approach, rather than making the method widely accessible. This work illustrates score-based diffusion models with a well-known problem in atmospheric science: cloud nowcasting (zero-to-three-hour forecast). After discussing the background and intuition of score-based diffusion models using examples from geostationary satellite infrared imagery, we experiment with three types of diffusion models: a standard score-based diffusion model (Diff); a residual correction diffusion model (CorrDiff); and a latent diffusion model (LDM). Our results show that the diffusion models not only advect existing clouds, but also generate and decay clouds, including convective initiation. A case study qualitatively shows the preservation of high-resolution features longer into the forecast than a conventional U-Net. The best of the three diffusion models tested was the CorrDiff approach, outperforming all other diffusion models, the conventional U-Net, and persistence. The diffusion models also enable out-of-the-box ensemble generation with skillful calibration. By explaining and exploring diffusion models for a common problem and ending with lessons learned from adapting diffusion models for our task, this work provides a starting point for the community to utilize diffusion models for a variety of earth science applications. - oai:arXiv.org:2505.10432v2 - cs.LG - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Reconnection-driven Flares in M87*: Proton-Synchrotron-powered GeV Emission + https://arxiv.org/abs/2507.14002 + arXiv:2507.14002v2 Announce Type: replace-cross +Abstract: Magnetic reconnection in current layers that form intermittently in radiatively inefficient accretion flows onto black holes is a promising mechanism for particle acceleration and high-energy emission. It has been recently proposed that such layers, arising during flux eruption events, can power the rapid TeV flares observed from the core of M87. In this scenario, inverse Compton scattering of soft radiation from the accretion flow by energetic electron-positron pairs produced near the reconnection layer was suggested as the primary emission mechanism. However, detailed calculations show that radiation from pairs alone cannot account for the GeV emission detected by the Fermi observatory. In this work, we combine analytic estimates with 3D radiative particle-in-cell simulations of pair-proton plasmas to show that the GeV emission can be naturally explained by synchrotron radiation from protons accelerated in the current sheet. Although the exact proton content of the layer is uncertain, our model remains robust across a broad range of proton-to-pair number density ratios. While protons are subdominant in number compared to pairs, our simulations demonstrate that they can be accelerated more efficiently, leading to a self-regulated steady state in which protons dominate the energy budget. Ultimately, proton synchrotron emission accounts for approximately 5%-20% of the total dissipation power. The majority is radiated as MeV photons via pair synchrotron emission, with a smaller fraction emitted as TeV photons through inverse Compton scattering. + oai:arXiv.org:2507.14002v2 + astro-ph.HE + physics.plasm-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Randy J. Chase, Katherine Haynes, Lander Ver Hoef, Imme Ebert-Uphoff + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + 10.3847/2041-8213/ae286a + The Astrophysical Journal Letters, Volume 995, Number 2, Pages L73, Dec 2025 + Hayk Hakobyan, Amir Levinson, Lorenzo Sironi, Alexander Philippov, Bart Ripperda - Long-term impact of PM2.5 on mortality is exacerbated when wildfire events occur - https://arxiv.org/abs/2505.16613 - arXiv:2505.16613v2 Announce Type: replace-cross -Abstract: There is extensive evidence that long-term exposure to all-source PM2.5 increases mortality. However, to date, no study has evaluated whether this effect is exacerbated in the presence of wildfire events. Here, we study 60+ million older US adults and find that wildfire events increase the harmful effects of long-term all-source PM2.5 exposure on mortality, providing a new and realistic conceptualization of wildfire health risks. - oai:arXiv.org:2505.16613v2 - q-bio.PE - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Deep Variational Free Energy Calculation of Hydrogen Hugoniot + https://arxiv.org/abs/2507.18540 + arXiv:2507.18540v2 Announce Type: replace-cross +Abstract: We develop a deep variational free energy framework to compute the equation of state of hydrogen in the warm dense matter region. This method parameterizes the variational density matrix of hydrogen nuclei and electrons at finite temperature using three deep generative models: a normalizing flow model for the Boltzmann distribution of the classical nuclei, an autoregressive transformer for the distribution of electrons in excited states, and a permutational equivariant flow model for the unitary backflow transformation of electron coordinates in Hartree-Fock states. By jointly optimizing the three neural networks to minimize the variational free energy, we obtain the equation of state and related thermodynamic properties of dense hydrogen for the temperature range where electrons occupy excited states. We compare our results with other theoretical and experimental results on the deuterium Hugoniot curve, aiming to resolve existing discrepancies. Our results bridge the gap between the results obtained by path-integral Monte Carlo calculations at high temperature and ground-state electronic methods at low temperature, thus providing a valuable benchmark for hydrogen in the warm dense matter region. + oai:arXiv.org:2507.18540v2 + cond-mat.str-el + cs.LG + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Federica Spoto, Francesca Dominici, Tarik Benmarhnia, Danielle Braun, Joan A. Casey + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Zihang Li, Hao Xie, Xinyang Dong, Lei Wang - PEAR: Equal Area Weather Forecasting on the Sphere - https://arxiv.org/abs/2505.17720 - arXiv:2505.17720v2 Announce Type: replace-cross -Abstract: Artificial intelligence is rapidly reshaping the natural sciences, with weather forecasting emerging as a flagship AI4Science application where machine learning models can now rival and even surpass traditional numerical simulations. Following the success of the landmark models Pangu Weather and Graphcast, outperforming traditional numerical methods for global medium-range forecasting, many novel data-driven methods have emerged. A common limitation shared by many of these models is their reliance on an equiangular discretization of the sphere which suffers from a much finer grid at the poles than around the equator. In contrast, in the Hierarchical Equal Area iso-Latitude Pixelization (HEALPix) of the sphere, each pixel covers the same surface area, removing unphysical biases. Motivated by a growing support for this grid in meteorology and climate sciences, we propose to perform weather forecasting with deep learning models which natively operate on the HEALPix grid. To this end, we introduce Pangu Equal ARea (PEAR), a transformer-based weather forecasting model which operates directly on HEALPix-features and outperforms the corresponding model on an equiangular grid without any computational overhead. - oai:arXiv.org:2505.17720v2 - cs.LG - physics.ao-ph - Mon, 22 Dec 2025 00:00:00 -0500 + High-magnitude, spatially programmable, and sustained strain engineering of 2D semiconductors + https://arxiv.org/abs/2508.00972 + arXiv:2508.00972v2 Announce Type: replace-cross +Abstract: Crystalline two-dimensional (2D) semiconductors often combine high elasticity and in-plane strength, making them ideal for strain-induced tuning of electronic characteristics, akin to strategies used in silicon electronics. However, existing techniques have not achieved strain in 2D materials that is simultaneously high in magnitude (>1%), stable over long periods, and spatially programmable, meaning the strain level can be deterministically engineered across different regions of a single 2D layer. Here, we apply spatially programmable biaxial strain (e_b) up to 2.2% with spatial resolution of 0.13 %e_b um-1 in monolayer MoS2 via conformal transfer onto patterned substrates fabricated using two-photon lithography. The induced strain is stable for months and enables local band gap tuning of ~0.4 eV in monolayer MoS2, ~25% of its intrinsic band gap. We further extend the approach to bilayer WS2-MoS2 heterostructures. This strain-engineering technique introduces a new regime of strain-enabled control in 2D semiconductors to support the development of wide-spectrum optoelectronic devices and nanoelectronics with engineered electronic landscapes. + oai:arXiv.org:2508.00972v2 + cond-mat.mtrl-sci + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Hampus Linander, Christoffer Petersson, Daniel Persson, Jan E. Gerken + Boran Kumral, Pedro Guerra Demingos, Peter Serles, Shuo Yang, Da Bin Kim, Dian Yu, Akhil Nair, Akshat Rastogi, Nima Barri, Md Akibul Islam, Jane Howe, Cristina H Amon, Sjoerd Hoogland, Edward H. Sargent, Chandra Veer Singh, Tobin Filleter - New Paradigm for Integrated Sensing and Communication with Rydberg Atomic Receiver - https://arxiv.org/abs/2506.13304 - arXiv:2506.13304v4 Announce Type: replace-cross -Abstract: The RYDberg Atomic Receiver (RYDAR) has been demonstrated to surmount the limitation on both the sensitivity and operating bandwidth of the classical electronic counterpart, which can theoretically detect indiscernible electric signals below -174 dBm/Hz with optical measurement through Rydberg-state atoms. Such miracle has established a new quantum-based paradigm for communications and sensing, which motivates a revolution of the transceiver design philosophies to fully unleash the potential of RYDAR towards next-generation networks. Against this background, this article provides a thorough investigation of Rydberg atomic communications and sensing from theory to hardware implementations. Specifically, we highlight the great opportunities from the hybridization between the RYDAR and the cutting-edge integrated sensing and communication (ISAC), followed by essential preliminaries of the quantum-based receiver. Then we propose a theoretical framework for broadband ISAC based on RYDAR, demonstrated by the proof-of-concept experiments. Afterwards, the enabling technologies for the ISAC framework are explored ranging from channel characterization, waveform design to array-based receiver configurations, where the open problems are also summarized. Finally, the future applications of RYDAR-based ISAC are envisioned, indicating its significant potential for both civilian and military purposes. - oai:arXiv.org:2506.13304v4 - quant-ph - physics.atom-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Data-driven particle dynamics: Structure-preserving coarse-graining for emergent behavior in non-equilibrium systems + https://arxiv.org/abs/2508.12569 + arXiv:2508.12569v2 Announce Type: replace-cross +Abstract: Multiscale systems are ubiquitous in science and technology, but are notoriously challenging to simulate as short spatiotemporal scales must be appropriately linked to emergent bulk physics. When expensive high-dimensional dynamical systems are coarse-grained into low-dimensional models, the entropic loss of information leads to emergent physics which are dissipative, history-dependent, and stochastic. To machine learn coarse-grained dynamics from time-series observations of particle trajectories, we propose a framework using the metriplectic bracket formalism that preserves these properties by construction; most notably, the framework guarantees discrete notions of the first and second laws of thermodynamics, conservation of momentum, and a discrete fluctuation-dissipation balance crucial for capturing non-equilibrium statistics. We introduce the mathematical framework abstractly before specializing to a particle discretization. As labels are generally unavailable for entropic state variables, we introduce a novel self-supervised learning strategy to identify emergent structural variables. We validate the method on benchmark systems and demonstrate its utility on two challenging examples: (1) coarse-graining star polymers at challenging levels of coarse-graining while preserving non-equilibrium statistics, and (2) learning models from high-speed video of colloidal suspensions that capture coupling between local rearrangement events and emergent stochastic dynamics. We provide open-source implementations in both PyTorch and LAMMPS, enabling large-scale inference and extensibility to diverse particle-based systems. + oai:arXiv.org:2508.12569v2 + cs.LG + cs.CE + physics.comp-ph + stat.ML + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Minze Chen, Tianqi Mao, Yang Zhao, Wei Xiao, Dezhi Zheng, Zhaocheng Wang, Jun Zhang, Sheng Chen + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Quercus Hernandez, Max Win, Thomas C. O'Connor, Paulo E. Arratia, Nathaniel Trask - Evaluation of Nuclear Microreactor Cost-competitiveness in Current Electricity Markets Considering Reactor Cost Uncertainties - https://arxiv.org/abs/2506.13361 - arXiv:2506.13361v2 Announce Type: replace-cross -Abstract: This paper evaluates the cost competitiveness of microreactors in today's electricity markets, with a focus on uncertainties in reactor costs. A Genetic Algorithm (GA) is used to optimize key technical parameters, such as reactor capacity, fuel enrichment, tail enrichment, refueling interval, and discharge burnup, to minimize the Levelized Cost of Energy (LCOE). Base case results are validated using Simulated Annealing (SA). By incorporating Probability Distribution Functions (PDFs) for fuel cycle costs, the study identifies optimal configurations under uncertainty. Methodologically, it introduces a novel framework combining probabilistic cost modeling with evolutionary optimization. Results show that microreactors can remain cost-competitive, with LCOEs ranging from \$48.21/MWh to \$78.32/MWh when supported by the Production Tax Credit (PTC). High reactor capacity, low fuel enrichment, moderate tail enrichment and refueling intervals, and high discharge burnup enhance cost efficiency. Among all factors, overnight capital cost (OCC) has the most significant impact on LCOE, while O&M and fuel cost uncertainties have lesser effects. The analysis highlights how energy policies like the PTC can reduce LCOE by 22-24%, improving viability despite cost variability. Compared to conventional nuclear, coal, and renewable sources like offshore wind, hydro, and biomass, optimized microreactors show strong economic potential. This research defines a realistic design space and key trade-offs, offering actionable insights for policymakers, reactor designers, and energy planners aiming to accelerate the deployment of affordable, sustainable microreactors. - oai:arXiv.org:2506.13361v2 - cs.NE - physics.soc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Predicting open quantum dynamics with data-informed quantum-classical dynamics + https://arxiv.org/abs/2508.17170 + arXiv:2508.17170v2 Announce Type: replace-cross +Abstract: We introduce a data-informed quantum-classical dynamics (DIQCD) approach for predicting the evolution of an open quantum system. The equation of motion in DIQCD is a Lindblad equation with a flexible, time-dependent Hamiltonian that can be optimized to fit sparse and noisy data from local observations of an extensive open quantum system. We demonstrate the accuracy and efficiency of DIQCD for both experimental and simulated quantum devices. We show that DIQCD can predict entanglement dynamics of ultracold molecules (Calcium Fluoride) in optical tweezer arrays. DIQCD also successfully predicts carrier mobility in organic semiconductors (Rubrene) with accuracy comparable to nearly exact numerical methods. + oai:arXiv.org:2508.17170v2 + quant-ph + cond-mat.stat-mech + physics.comp-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - 10.1016/j.nucengdes.2025.114295 - Nuclear Engineering and Design 443 (2025) 114295 - Muhammad R. Abdussami, Ikhwan Khaleb, Fei Gao, Aditi Verma + 10.1103/7lsx-ssjl + Pinchen Xie, Ke Wang, Anupam Mitra, Yuanran Zhu, Xiantao Li, Wibe Albert de Jong, Chao Yang - Fidelity Relations in an Array of Neutral Atom Qubits -- Experimental Validation of Control Noise - https://arxiv.org/abs/2506.16974 - arXiv:2506.16974v2 Announce Type: replace-cross -Abstract: Noise is a hindering factor for current-era quantum computers. In this study, we experimentally validate the theoretical relationships between amplitude noise of the control signal and qubit state fidelity. The experiment comprises a 10x10 site optical tweezer array stochastically loaded with single rubidium-85 atoms. A global microwave field is used to manipulate the state of the hyperfine qubits. With precise control of the time-dependent amplitude of the microwave drive, we apply control signals featuring artificial noise. We systematically analyze the impact of various noise profiles on the fidelity distribution of the quantum states. The measured fidelities are compared against theoretical predictions made using the stochastic Schr\"odinger equation. Our results show a good agreement between the experimentally measured and theoretically predicted results. This validation is consequential, as the model provides critical information on noise identification and optimal control protocols in NISQ-era quantum systems. - oai:arXiv.org:2506.16974v2 - quant-ph - physics.atom-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Controlling the collective transport of large passive particles with suspensions of microorganisms + https://arxiv.org/abs/2509.08133 + arXiv:2509.08133v2 Announce Type: replace-cross +Abstract: A promising approach to transport cargo at the microscale lies within the use of self-propelled microorganisms, whose motion entrains that of passive particles. However, most applications remain limited to just a few passive particles of similar size as the microorganisms, since the transport mechanism relies on the interaction between individual swimmers and single particles. Here, we demonstrate how to control the collective transport of hundreds of large passive particles with phototactic microalga. Using directional light stimuli in suspensions of Chlamydomonas reinhardtii, we trigger bioconvection rolls capable of macroscale transport. Passive particles an order of magnitude larger than the microalgae are either attracted or repelled by the rolls depending on their density. Using experiments and simulation, we rationalize these bioconvective flows and describe how to harness them for cargo transport, with future applications in targeted drug delivery and decontamination. + oai:arXiv.org:2509.08133v2 + cond-mat.soft + physics.bio-ph + physics.flu-dyn + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Deon Janse van Rensburg, Robert de Keijzer, Rogier Venderbosch, Yuri van der Werf, Jesus del Pozo Mellado, Rianne Lous, Edgar Vredenbregt, Servaas Kokkelmans + Taha Laroussi, Julien Bouvard, Etienne Jambon-Puillet, Mojtaba Jarrahi, Gabriel Amselem - Instability of explicit time integration for strongly quenched dynamics with neural quantum states - https://arxiv.org/abs/2507.17421 - arXiv:2507.17421v2 Announce Type: replace-cross -Abstract: Neural quantum states have recently demonstrated significant potential for simulating quantum dynamics beyond the capabilities of existing variational ans\"{a}tze. However, studying strongly driven quantum dynamics with neural networks has proven challenging so far. Here, we focus on assessing several sources of numerical instabilities that can appear in the simulation of quantum dynamics based on the time-dependent variational principle (TDVP) with the computationally efficient explicit time integration scheme. Focusing on the restricted Boltzmann machine architecture, we compare solutions obtained by TDVP with analytical solutions and implicit methods as a function of the quench strength. Interestingly, we uncover a quenching strength that leads to a numerical breakdown in the absence of Monte Carlo noise, despite the fact that physical observables don't exhibit irregularities. This breakdown phenomenon appears consistently across several different TDVP formulations, even those that eliminate small eigenvalues of the Fisher matrix or use geometric properties to recast the equation of motion. We provide evidence that the nature of the instability stems from stiffness of the dynamics of the variational parameters, despite the absence of stiffness in the exact quantum dynamics. We conclude that alternative methods need to be developed to leverage the computational efficiency of explicit time integration of the TDVP equations for simulating strongly nonequilibrium quantum dynamics with neural-network quantum states. - oai:arXiv.org:2507.17421v2 - quant-ph - cond-mat.dis-nn - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Multimodal Neural Operators for Real-Time Biomechanical Modelling of Traumatic Brain Injury + https://arxiv.org/abs/2510.03248 + arXiv:2510.03248v2 Announce Type: replace-cross +Abstract: Background: Traumatic brain injury (TBI) is a major global health concern with 69 million annual cases. While neural operators have revolutionized scientific computing, existing architectures cannot handle the heterogeneous multimodal data (anatomical imaging, scalar demographics, and geometric constraints) required for patient-specific biomechanical modeling. Objective: This study introduces the first multimodal neural operator framework for biomechanics, fusing heterogeneous inputs to predict brain displacement fields for rapid TBI risk assessment. Methods: TBI modeling was reformulated as a multimodal operator learning problem. We proposed two fusion strategies: field projection for Fourier Neural Operator (FNO) architectures and branch decomposition for Deep Operator Networks (DeepONet). Four architectures (FNO, Factorized FNO, Multi-Grid FNO, and DeepONet) were extended with fusion mechanisms and evaluated on 249 in vivo Magnetic Resonance Elastography (MRE) datasets (20-90 Hz). Results: Multi-Grid FNO achieved the highest accuracy (MSE = 0.0023, 94.3% spatial fidelity). DeepONet offered the fastest inference (14.5 iterations/s, 7x speedup), suitable for edge deployment. All architectures reduced computation from hours to milliseconds. Conclusion: Multimodal neural operators enable efficient, real-time, patient-specific TBI risk assessment. This framework establishes a generalizable paradigm for heterogeneous data fusion in scientific domains, including precision medicine. + oai:arXiv.org:2510.03248v2 + cs.LG + cs.AI + cs.CV + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Hrvoje Vrcan, Johan H. Mentink + Anusha Agarwal, Dibakar Roy Sarkar, Somdatta Goswami - Characterizing and Mitigating Flux Crosstalk in Superconducting Qubits-Couplers System - https://arxiv.org/abs/2508.03434 - arXiv:2508.03434v3 Announce Type: replace-cross -Abstract: Superconducting qubits have achieved exceptional gate fidelities, exceeding the error-correction threshold in recent years. One key ingredient of such improvement is the introduction of tunable couplers to control the qubit-to-qubit coupling through frequency tuning. Moving toward fault-tolerant quantum computation, increasing the number of physical qubits is another step toward effective error correction codes. Under a multiqubit architecture, flux control (Z) lines are crucial in tuning the frequency of the qubits and couplers. However, dense flux lines result in magnetic flux crosstalk, wherein magnetic flux applied to one element inadvertently affects neighboring qubits or couplers. This crosstalk obscures the idle frequency of the qubit when flux bias is applied, which degrades gate performance and calibration accuracy. In this study, we characterize flux crosstalk and suppress it in a multiqubit-coupler chip with multi-Z lines without adding additional readout for couplers. By quantifying the mutual flux-induced frequency shifts of qubits and couplers, we construct a cancellation matrix that enables precise compensation of non-local flux, demonstrating a substantial reduction in Z-line crosstalk from 56.5$\,$permille$\,$to 0.13$\,$permille$\,$ which is close to statistical error. Flux compensation corrects the CZ SWAP measurement, leading to a symmetric map with respect to flux bias. Compared with a crosstalk-free calculated CZ SWAP map, the measured map indicates that our approach provides a near-zero crosstalk for the coupler-transmon system. These results highlight the effectiveness of our approach in enhancing flux crosstalk-free control and supporting its potential for scaling superconducting quantum processors. - oai:arXiv.org:2508.03434v3 + Motional entanglement in low-energy collisions near shape resonances + https://arxiv.org/abs/2511.02925 + arXiv:2511.02925v2 Announce Type: replace-cross +Abstract: Einstein, Podolsky, and Rosen discussed their paradox in terms of measuring the positions or momenta of two particles. These degrees of freedom can become entangled upon scattering, but how much entanglement can be created in this process? Here we address this question using fully coherent calculations of bipartite scattering in three-dimensional space, quantifying entanglement by the inverse of the single particle purity. We show that the standard plane-wave description of scattering fails to capture the entanglement properties, due to the essential role of quantum uncertainty in the initial state. For a more realistic description of a scattering setup, we find that the entanglement scales linearly with the scattering cross section, including strong enhancement near shape resonances, for sufficiently narrow initial momentum dispersion. We highlight the differences between scattering in one and higher spatial dimensions and discuss how the generation of motional entanglement can be detected in experiments. Our results open the way to probing, controlling, and eventually using entanglement in quantum collisions. + oai:arXiv.org:2511.02925v2 quant-ph - physics.app-ph - Mon, 22 Dec 2025 00:00:00 -0500 + physics.atom-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by-nc-sa/4.0/ - Myrron Albert Callera Aguila, Nien-Yu Li, Chen-Hsun Ma, Li-Chieh Hsiao, Yi-Shiang Huang, Yen-Chun Chen, Teik-Hui Lee, Chin-Chia Chang, Jyh-Yang Wang, Ssu-Yen Huang, Hsi-Sheng Goan, Chiao-Hsuan Wang, Cen-Shawn Wu, Chii-Dong Chen, Chung-Ting Ke + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Yimeng Wang, Christiane P. Koch - Applied causality to infer protein dynamics and kinetics - https://arxiv.org/abs/2508.12060 - arXiv:2508.12060v2 Announce Type: replace-cross -Abstract: The use of generative machine learning models, trained on the experimentally resolved structures deposited in the protein data bank, is an attractive approach to sampling conformational ensembles of proteins. However, the ensembles generated by these models lack timescale or causal information. We use the structural ensembles generated from AlphaFold2 at a range of MSA depths to parameterize the potential of mean force of an overdamped, memory-free, coarse-grained Langevin equation. This approach couples the AlphaFold2 ensembles to a causal model, allowing us to estimate the timescales spanned by the ensembles generated at each MSA depth. Performing this analysis on six variants of HIV-1 protease, we confirm an inverse relationship between MSA depth and the timescale of an ensemble's conformational fluctuations. The MSA depth essentially serves as a conformational restraint, and AlphaFold2 is generally able to probe timescales at or below those seen in microsecond-long, unbiased molecular dynamics simulations. We conclude by generalizing this approach to other generative structural ensemble-prediction methods as well as co-folding models, in this case the biologically functional HIV-1 protease dimer. - oai:arXiv.org:2508.12060v2 - q-bio.BM - physics.bio-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Nowcast3D: Reliable precipitation nowcasting via gray-box learning + https://arxiv.org/abs/2511.04659 + arXiv:2511.04659v3 Announce Type: replace-cross +Abstract: Extreme-precipitation nowcasting requires high spatial and temporal resolution together with extended lead times, yet current approaches remain constrained. Numerical weather prediction systems and their deep-learning emulators operate at relatively coarse space-time resolution and struggle to capture rapidly evolving convective systems. Radar extrapolation methods, which advect recent fields using estimated motion, have difficulty capturing the complex evolution of precipitation. Purely data-driven models often produce overly smoothed reflectivity fields and underestimate intensity. Hybrid 2D radar-based methods discard crucial vertical information, preventing accurate reconstruction of height-dependent dynamics. We introduce Nowcast3D, a gray-box, fully three-dimensional nowcasting framework that operates directly on volumetric radar reflectivity and couples physically constrained neural operators with data-driven learning. The model learns three fields that govern reflectivity evolution: a three-dimensional flow field for advective transport, a spatially varying diffusion field for local dispersive spreading, and a residual source term for unresolved microphysical effects. These learned operators advance the forecast in time under explicit physical constraints, while a conditional diffusion model, conditioned on both the observations and the physics-based forecast, generates ensembles of future radar volumes that quantify forecast uncertainty. In a blind evaluation by 160 meteorologists, Nowcast3D is preferred in 57% of post-hoc and 51% of prior assessments. By explicitly embedding three-dimensional dynamics and uncertainty into a single framework, Nowcast3D offers a scalable and robust approach for reliable nowcasting of extreme precipitation. + oai:arXiv.org:2511.04659v3 + cs.LG + physics.ao-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - Akashnathan Aranganathan, Eric R. Beyerle + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Huaguan Chen, Wei Han, Haofei Sun, Ning Lin, Xingtao Song, Yunfan Yang, Jie Tian, Yang Liu, Ji-Rong Wen, Xiaoye Zhang, Xueshun Shen, Hao Sun - Local Order Average-Atom Interatomic Potentials - https://arxiv.org/abs/2510.06459 - arXiv:2510.06459v3 Announce Type: replace-cross -Abstract: This article describes an extension to the effective Average Atom (AA) method for random alloys to account for local ordering (short-range order) effects by utilizing information from partial radial distribution functions. The new Local-Order Average Atom (LOAA) method is rigorously derived based on statistical mechanics arguments and validated for non-stoichiometric binary 2D hexagonal crystals and 3D FeNiCr and NiAl alloys whose ground state is obtained through Monte Carlo sampling. Material properties for these alloys, and phase transformations for the NiAl system, computed from static and dynamic atomistic simulations using standard interatomic potentials (IPs) exhibit a strong dependence on local ordering that is captured by simulations with effective LOAA IPs, but not the original AA method. The advantage of LOAA is that it requires smaller system sizes to achieve statistically converged results and therefore enables the simulation of complex materials, such as high-entropy alloys, at a fraction of the computational cost of standard IPs. - oai:arXiv.org:2510.06459v3 - cond-mat.mtrl-sci + Superradiant decay in non-Markovian Waveguide Quantum Electrodynamics + https://arxiv.org/abs/2511.22332 + arXiv:2511.22332v2 Announce Type: replace-cross +Abstract: An array of initially excited emitters coupled to a one-dimensional waveguide exhibits superradiant decay under the Born-Markov approximation, manifested as a coherent burst of photons in the output field. In this work, we employ tensor-network methods to investigate its non-Markovian dynamics induced by finite time delays in photon exchange among the emitters. We find that the superradiant burst breaks into a structured train of correlated photons, each intensity peak corresponding to a specific photon number. We quantify the emitter-photon and emitter-emitter entanglement generated during this process and show that the latter emerges in the long-time limit, as part of the excitation becomes trapped within the emitters' singlet subspace. We finally consider the decay of the system's most radiant state, the symmetric Dicke state, and show that time delay can lead to decay rates exceeding those predicted by the Markovian approximation. + oai:arXiv.org:2511.22332v2 + quant-ph + cond-mat.mes-hall + physics.atom-ph physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Chloe A. Zeller, Ronald E. Miller, Ellad B. Tadmor + Rosa Lucia Capurso, Giuseppe Calaj\'o, Simone Montangero, Saverio Pascazio, Francesco V. Pepe, Maria Maffei, Giuseppe Magnifico, Paolo Facchi - Quantum Generative Modeling of Single-Cell transcriptomes: Capturing Gene-Gene and Cell-Cell Interactions - https://arxiv.org/abs/2510.12776 - arXiv:2510.12776v3 Announce Type: replace-cross -Abstract: Single-cell RNA sequencing (scRNA-seq) data simulation is limited by classical methods that rely on linear correlations, failing to capture the intrinsic, nonlinear dependencies. No existing simulator jointly models gene-gene and cell-cell interactions. We introduce qSimCells, a novel quantum computing-based simulator that employs entanglement to model intra- and inter-cellular interactions, generating realistic single-cell transcriptomes with cellular heterogeneity. The core innovation is a quantum kernel that uses a parameterized quantum circuit with CNOT gates to encode complex, nonlinear gene regulatory network (GRN) as well as cell-cell communication topologies with explicit causal directionality. The resulting synthetic data exhibits non-classical dependencies: standard correlation-based analyses (Pearson and Spearman) fail to recover the programmed causal pathways and instead report spurious associations driven by high baseline gene-expression probabilities. Furthermore, applying cell-cell communication detection to the simulated data validates the true mechanistic links, revealing a robust, up to 75-fold relative increase in inferred communication probability only when quantum entanglement is active. These results demonstrate that the quantum kernel is essential for producing high-fidelity ground-truth datasets and highlight the need for advanced inference techniques to capture the complex, non-classical dependencies inherent in gene regulation. - oai:arXiv.org:2510.12776v3 - q-bio.QM - cs.ET - physics.bio-ph - q-bio.GN - Mon, 22 Dec 2025 00:00:00 -0500 + ASPEN: An Adaptive Spectral Physics-Enabled Network for Ginzburg-Landau Dynamics + https://arxiv.org/abs/2512.03290 + arXiv:2512.03290v3 Announce Type: replace-cross +Abstract: Physics-Informed Neural Networks (PINNs) have emerged as a powerful, mesh-free paradigm for solving partial differential equations (PDEs). However, they notoriously struggle with stiff, multi-scale, and nonlinear systems due to the inherent spectral bias of standard multilayer perceptron (MLP) architectures, which prevents them from adequately representing high-frequency components. In this work, we introduce the Adaptive Spectral Physics-Enabled Network (ASPEN), a novel architecture designed to overcome this critical limitation. ASPEN integrates an adaptive spectral layer with learnable Fourier features directly into the network's input stage. This mechanism allows the model to dynamically tune its own spectral basis during training, enabling it to efficiently learn and represent the precise frequency content required by the solution. We demonstrate the efficacy of ASPEN by applying it to the complex Ginzburg-Landau equation (CGLE), a canonical and challenging benchmark for nonlinear, stiff spatio-temporal dynamics. Our results show that a standard PINN architecture catastrophically fails on this problem, diverging into non-physical oscillations. In contrast, ASPEN successfully solves the CGLE with exceptional accuracy. The predicted solution is visually indistinguishable from the high-resolution ground truth, achieving a low median physics residual of 5.10 x 10^-3. Furthermore, we validate that ASPEN's solution is not only pointwise accurate but also physically consistent, correctly capturing emergent physical properties, including the rapid free energy relaxation and the long-term stability of the domain wall front. This work demonstrates that by incorporating an adaptive spectral basis, our framework provides a robust and physically-consistent solver for complex dynamical systems where standard PINNs fail, opening new options for machine learning in challenging physical domains. + oai:arXiv.org:2512.03290v3 + cs.LG + physics.app-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Selim Romero, Vignesh S. Kumar, Robert S. Chapkin, James J. Cai + Julian Evan Chrisnanto, Nurfauzi Fadillah, Yulison Herry Chrisnanto - Modeling Diffusion and Permeation Across the Stratum Corneum Lipid Barrier - https://arxiv.org/abs/2510.14606 - arXiv:2510.14606v2 Announce Type: replace-cross -Abstract: Human skin oils are a major sink for ozone in densely occupied indoor environments. Understanding how the resulting volatile and semivolatile organic oxidation products influence indoor air chemistry requires accurate representations not only of their emission into indoor air but also of their transport across the outermost skin barrier, the stratum corneum. Using molecular dynamics simulations, we investigate the passive permeation of acetone, 6-methyl-5-hepten-2-one, and water -- two representative products of skin-oil oxidation and a reference compound -- through a model stratum corneum lipid membrane. We determine position-dependent diffusivities using two complementary analyses based on the same set of simulations and evaluate their accuracy through a propagator analysis. The two approaches provide upper and lower bounds for the true diffusivity, which, when combined with previously reported free-energy profiles, yield permeabilities relevant for modeling macroscopic skin transport. Our results show that permeation is governed primarily by energetic barriers rather than by molecular mobility, and that the predicted transport coefficients vary by about one order of magnitude depending on the chosen diffusivity estimator. These findings provide molecular-level constraints for parameters used in indoor air chemistry models and establish a transferable framework for linking atomistic transport mechanisms to large-scale simulations of human exposure and indoor air quality. - oai:arXiv.org:2510.14606v2 - cond-mat.soft - physics.bio-ph - physics.chem-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Robust AC vector sensing at zero magnetic field with pentacene + https://arxiv.org/abs/2512.06272 + arXiv:2512.06272v2 Announce Type: replace-cross +Abstract: Quantum sensors based on electronic spins have emerged as powerful probes of microwave-frequency fields. Among other solid-state platforms, spins in molecular crystals offer a range of advantages, from high spin density to functionalization via chemical tunability. Here, we demonstrate microwave vector magnetometry using the photoexcited spin triplet of deuterated pentacene molecules, operating at zero external magnetic field and room temperature. We achieve full three-dimensional microwave field reconstruction by detecting the Rabi frequencies of anisotropic spin-triplet transitions associated with two crystallographic orientations of pentacene in naphthalene crystals. We further introduce a phase alternated protocol that extends the rotating-frame coherence time by an order of magnitude and enables sensitivities of $1~\mu\mathrm{T}/\sqrt{\mathrm{Hz}}$ with sub-micrometer spatial resolution. These results establish pentacene-based molecular spins as a practical and high-performance platform for microwave quantum sensing, and the control techniques are broadly applicable to other molecular and solid-state spin systems. + oai:arXiv.org:2512.06272v2 + cond-mat.mes-hall + physics.app-ph + quant-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Rinto Thomas, Praveen Ranganath Prabhakar, Douglas J. Tobias, Michael von Domaros + Boning Li, Garrett Heller, Jungbae Yoon, Alexander Ungar, Hao Tang, Guoqing Wang, Patrick Hautle, Yifan Quan, Paola Cappellaro - Training Deep Physics-Informed Kolmogorov-Arnold Networks - https://arxiv.org/abs/2510.23501 - arXiv:2510.23501v2 Announce Type: replace-cross -Abstract: Since their introduction, Kolmogorov-Arnold Networks (KANs) have been successfully applied across several domains, with physics-informed machine learning (PIML) emerging as one of the areas where they have thrived. In the PIML setting, Chebyshev-based physics-informed KANs (cPIKANs) have become the standard due to their computational efficiency. However, like their multilayer perceptron-based counterparts, cPIKANs face significant challenges when scaled to depth, leading to training instabilities that limit their applicability to several PDE problems. To address this, we propose a basis-agnostic, Glorot-like initialization scheme that preserves activation variance and yields substantial improvements in stability and accuracy over the default initialization of cPIKANs. Inspired by the PirateNet architecture, we further introduce Residual-Gated Adaptive KANs (RGA KANs), designed to mitigate divergence in deep cPIKANs where initialization alone is not sufficient. Through empirical tests and information bottleneck analysis, we show that RGA KANs successfully traverse all training phases, unlike baseline cPIKANs, which stagnate in the diffusion phase in specific PDE settings. Evaluations on nine standard forward PDE benchmarks under a fixed training pipeline with adaptive components demonstrate that RGA KANs consistently outperform parameter-matched cPIKANs and PirateNets - often by several orders of magnitude - while remaining stable in settings where the others diverge. - oai:arXiv.org:2510.23501v2 - cs.LG + Py-DiSMech: A Scalable and Efficient Framework for Discrete Differential Geometry-Based Modeling and Control of Soft Robots + https://arxiv.org/abs/2512.09911 + arXiv:2512.09911v2 Announce Type: replace-cross +Abstract: High-fidelity simulation has become essential to the design and control of soft robots, where large geometric deformations and complex contact interactions challenge conventional modeling tools. Recent advances in the field demand simulation frameworks that combine physical accuracy, computational scalability, and seamless integration with modern control and optimization pipelines. In this work, we present Py-DiSMech, a Python-based, open-source simulation framework for modeling and control of soft robotic structures grounded in the principles of Discrete Differential Geometry (DDG). By discretizing geometric quantities such as curvature and strain directly on meshes, Py-DiSMech captures the nonlinear deformation of rods, shells, and hybrid structures with high fidelity and reduced computational cost. The framework introduces (i) a fully vectorized NumPy implementation achieving order-of-magnitude speed-ups over existing geometry-based simulators; (ii) a penalty-energy-based fully implicit contact model that supports rod-rod, rod-shell, and shell-shell interactions; (iii) a natural-strain-based feedback-control module featuring a proportional-integral (PI) controller for shape regulation and trajectory tracking; and (iv) a modular, object-oriented software design enabling user-defined elastic energies, actuation schemes, and integration with machine-learning libraries. Benchmark comparisons demonstrate that Py-DiSMech substantially outperforms the state-of-the-art simulator Elastica in computational efficiency while maintaining physical accuracy. Together, these features establish Py-DiSMech as a scalable, extensible platform for simulation-driven design, control validation, and sim-to-real research in soft robotics. + oai:arXiv.org:2512.09911v2 + cs.RO physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 + replace-cross + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Radha Lahoti, Ryan Chaiyakul, M. Khalid Jawed + + + Renormalization group for spectral collapse in random matrices with power-law variance profiles + https://arxiv.org/abs/2512.13883 + arXiv:2512.13883v2 Announce Type: replace-cross +Abstract: We propose a renormalization group (RG) approach to compare and collapse eigenvalue densities of random matrix models of complex systems across different system sizes. The approach is to fix a natural spectral scale by letting the model normalization run with size, turning raw spectra into comparable, collapsed density curves. We demonstrate this approach on generalizations of two classic random matrix ensembles--Wigner and Wishart--modified to have power-law variance profiles. We use random matrix theory methods to derive self-consistent fixed-point equations for the resolvent to compute their eigenvalue densities, we define an RG scheme based on matrix decimation, and compute the Beta function controlling the RG flow as a function of the variance profile power-law exponent. The running normalization leads to spectral collapse which we confirm in simulations and solutions of the fixed-point equations. We expect this RG approach to carry over to other ensembles, providing a method for data analysis of a broad range of complex systems. + oai:arXiv.org:2512.13883v2 + cond-mat.stat-mech + physics.data-an + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross http://creativecommons.org/licenses/by/4.0/ - Spyros Rigas, Fotios Anagnostopoulos, Michalis Papachristou, Georgios Alexandridis + Philipp Fleig - Beyond Exascale: Dataflow Domain Translation on a Cerebras Cluster - https://arxiv.org/abs/2511.11542 - arXiv:2511.11542v2 Announce Type: replace-cross -Abstract: Simulation of physical systems is essential across scientific and engineering domains. Commonly used domain decomposition methods are unable to simultaneously deliver both high simulation rate and high utilization in network computing environments. In particular, Exascale systems deliver only a small fraction their peak performance for these workloads. This paper introduces the novel Domain Translation algorithm, designed to overcome these limitations. On a cluster of 64 Cerebras CS-3 systems, we use this method to demonstrate unprecedented cluster performance across a range of metrics: we show simulations running in excess of 1.6 million time steps per second; we also demonstrate perfect weak scaling at 88% of peak performance. At this cluster scale, our implementation provides 112 PFLOP/s in a power-unconstrained environment, and 57 GFLOP/J in a power-limited environment. We illustrate the method by applying the shallow-water equations to model a tsunami following an asteroid impact at 460m-resolution on a planetary scale. - oai:arXiv.org:2511.11542v2 - cs.DC - physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Decomposing Non-Markovian History Dependence + https://arxiv.org/abs/2512.13933 + arXiv:2512.13933v2 Announce Type: replace-cross +Abstract: Non-Markovian stochastic processes are ubiquitous in biology. Nevertheless, we lack a general framework for quantifying historical dependencies. In this Letter, we propose an information-theoretic approach to decompose history dependence in systems with non-Markovian dynamics, quantifying the information encoded in dependencies of each order. In minimal models of non-Markovian dynamics, we show that this framework correctly captures the underlying historical dependencies, even when autocorrelations do not. In prolonged recordings of fly behavior, we find that the scaling of non-Markovian dependencies is invariant across timescales from fractions of a second to minutes. Despite this invariance, the overall amount of non-Markovian information is non-monotonic, suggesting a unique timescale on which historical dependencies are strongest. + oai:arXiv.org:2512.13933v2 + cond-mat.stat-mech + physics.bio-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by-nc-nd/4.0/ - 10.1145/3773656.3773683 - Tomas Oppelstrup, Nicholas Giamblanco, Delyan Z. Kalchev, Ilya Sharapov, Mark Taylor, Dirk Van Essendelft, Sivasankaran Rajamanickam, Michael James + http://arxiv.org/licenses/nonexclusive-distrib/1.0/ + Matthew P. Leighton, Christopher W. Lynn - Spectroscopic readout of chiral photonic topology in a single-cavity spin-orbit-coupled Bose-Einstein condensate - https://arxiv.org/abs/2512.08662 - arXiv:2512.08662v2 Announce Type: replace-cross -Abstract: Topological photonic phases are typically identified through band reconstruction, steady-state transmission, or real-space imaging of edge modes. In this work, we present a framework for spectroscopic readout of chiral photonic topology in a single driven optical cavity containing a spin-orbit-coupled Bose-Einstein condensate. We demonstrate that the cavity transmission power spectral density provides a direct and measurable proxy for a momentum- and frequency-resolved photonic Chern marker, enabling topological characteristics to be inferred from spectral data without the need for bulk-band tomography. In the loss-dominated regime, where cavity decay exceeds atomic dissipation, the power spectral density exhibits Dirac-like gapped hybrid modes with a vanishing Chern marker, indicating a trivial phase. When the dissipation imbalance is reversed, a bright, gap-spanning spectral ridge emerges, co-localized with peaks in both the Chern marker and Berry curvature. The complex spectrum reveals parity-time symmetric coalescences and gain-loss bifurcations, marking exceptional points and enabling chiral, gap-traversing transport. By linking noise spectroscopy to geometric and non-Hermitian topology in a minimal cavity-QED architecture, this work provides a framework for spectroscopic detection of topological order in driven quantum systems. This approach offers a pathway to compact, tunable topological photonics across a broad range of light-matter platforms, providing a method for the study and control of topological phases in hybrid quantum systems. - oai:arXiv.org:2512.08662v2 + Instantaneous velocity during quantum tunnelling + https://arxiv.org/abs/2512.16385 + arXiv:2512.16385v2 Announce Type: replace-cross +Abstract: Quantum tunnelling, a hallmark phenomenon of quantum mechanics, allows particles to pass through the classically forbidden region. It underpins fundamental processes ranging from nuclear fusion and photosynthesis to the operation of superconducting qubits. Yet the underlying dynamics of particle motion during tunnelling remain subtle and are still the subject of active debate. Here, by analyzing the temporal evolution of the tunnelling process, we show that the particle velocity inside the barrier continuously relaxes from a large initial value toward a smaller one, and may even approach zero in the evanescent regime. Meanwhile, the probability density within the barrier gradually builds up before reaching its stationary profile, in contrast to existing inherently. In addition, starting from the steady-state equations, we derive an explicit relation between the particle velocity and the barrier width, and show that the velocity in evanescent states approaches zero when the barrier is sufficiently wide. These findings resolve the apparent paradox of a vanishing steady-state velocity coexisting with a finite particle density. We point out that defining an effective speed from the probability density, rather than from the probability current, can lead to spuriously nonzero "stationary speed," as appears to be the case in Ref. [Nature 643, 67 (2025)]. Our work establishes a clear dynamical picture for the formation of tunnelling flow and provides a theoretical foundation for testing time-resolved tunnelling phenomena. + oai:arXiv.org:2512.16385v2 quant-ph - cond-mat.quant-gas - physics.app-ph physics.optics - Mon, 22 Dec 2025 00:00:00 -0500 + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Kashif Ammar Yasir, Gao Xianlong + http://creativecommons.org/licenses/by-nc-sa/4.0/ + Xiao-Wen Shang, Jian-Peng Dou, Feng Lu, Sen Lin, Hao Tang, Xian-Min Jin - Frequency Extraction from Invariant Flows - https://arxiv.org/abs/2512.16060 - arXiv:2512.16060v2 Announce Type: replace-cross -Abstract: In non-degenerate integrable Hamiltonian systems, invariant tori can be parameterized equivalently by action variables or by their fundamental frequencies. We introduce an invariant-flow formulation for extracting fundamental frequencies of integrable Hamiltonian systems. By treating invariants as generators of commuting Hamiltonian flows, the frequencies are obtained from time-of-flight parameters along these flows, providing a direct alternative to action-angle constructions and spectral methods based on long time series. The approach yields an explicit numerical procedure that extends naturally to systems with multiple degrees of freedom. Its effectiveness is demonstrated using the McMillan map, where machine-precision accuracy is achieved. - oai:arXiv.org:2512.16060v2 - nlin.SI - physics.acc-ph - Mon, 22 Dec 2025 00:00:00 -0500 + Subsystems (in)dependence in GIE proposals + https://arxiv.org/abs/2512.17024 + arXiv:2512.17024v2 Announce Type: replace-cross +Abstract: Recent proposals suggest that detecting entanglement between two spatially superposed masses would establish the quantum nature of gravity. However, these gravitationally induced entanglement (GIE) experiments rely on assumptions about subsystem independence. We sharpen the theoretical underpinnings of such proposals by examining them through the lens of algebraic quantum field theory (AQFT), distinguishing distinct operational and algebraic notions of independence. We argue that state and measurement independence of subsystems, essential to the experimental logic, is nontrivial in the presence of gauge constraints and gravitational dressing. Using gravitationally dressed fields, we recall that commutation relations between spacelike separated observables are nontrivial, undermining strict Hilbert space factorization. We further explore the implications for entanglement witnesses, investigating the Tsirelson bound when subsystem algebras fail to commute, and showing that the Tsirelson bound persists for a suitably symmetrized CHSH observable even though the operational status of such "joint" observables becomes delicate when commensurability fails. Our analysis highlights how even within linearized covariant quantum gravity, violations of microcausality may affect both the interpretation, modelling, and design of proposed laboratory tests of quantum gravity, despite remaining negligible for current experimental regimes. Although we consider GIE-style protocols as a concrete case study, the subsystem-independence issues we highlight are generic to low-energy (perturbative) quantum gravity. Finally, we derive estimates for dressing-induced microcausality violations, which suggest a complementary avenue to current proposals: in principle, bounding dressing-induced microcausality violations themselves as a probe of the quantum nature of gravity. + oai:arXiv.org:2512.17024v2 + quant-ph + hep-th + math-ph + math.MP + physics.hist-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://arxiv.org/licenses/nonexclusive-distrib/1.0/ - Derong Xu, Yongjun Li, Yue Hao, Sergei Nagaitsev + http://creativecommons.org/licenses/by/4.0/ + Nicolas Boulle, Guilherme Franzmann - Efficient Monte-Carlo sampling of metastable systems using non-local collective variable updates - https://arxiv.org/abs/2512.16812 - arXiv:2512.16812v2 Announce Type: replace-cross -Abstract: Monte-Carlo simulations are widely used to simulate complex molecular systems, but standard approaches suffer from metastability. Lately, the use of non-local proposal updates in a collective-variable (CV) space has been proposed in several works. Here, we generalize these approaches and explicitly spell out an algorithm for non-linear CVs and underdamped Langevin dynamics. We prove reversibility of the resulting scheme and demonstrate its performance on several numerical examples, observing a substantial performance increase compared to methods based on overdamped Langevin dynamics as considered previously. Advances in generative machine-learning-based proposal samplers now enable efficient sampling in CV spaces of intermediate dimensionality (tens to hundreds of variables), and our results extend their applicability toward more realistic molecular systems. - oai:arXiv.org:2512.16812v2 - cond-mat.stat-mech + Estimating Spatially Resolved Radiation Fields Using Neural Networks + https://arxiv.org/abs/2512.17654 + arXiv:2512.17654v2 Announce Type: replace-cross +Abstract: We present an in-depth analysis on how to build and train neural networks to estimate the spatial distribution of scattered radiation fields for radiation protection dosimetry in medical radiation fields, such as those found in interventional radiology and cardiology. We present three different synthetically generated datasets with increasing complexity for training, using a Monte-Carlo Simulation application based on Geant4. On those datasets, we evaluate convolutional and fully connected architectures of neural networks to demonstrate which design decisions work well for reconstructing the fluence and spectra distributions over the spatial domain of such radiation fields. All our datasets, as well as our training pipeline, are published as open source in separate repositories. + oai:arXiv.org:2512.17654v2 + cs.LG physics.comp-ph - Mon, 22 Dec 2025 00:00:00 -0500 + physics.med-ph + Tue, 23 Dec 2025 00:00:00 -0500 replace-cross - http://creativecommons.org/licenses/by/4.0/ - Christoph Sch\"onle, Davide Carbone, Marylou Gabri\'e, Tony Leli\`evre, Gabriel Stoltz + http://creativecommons.org/licenses/by-sa/4.0/ + Felix Lehner, Pasquale Lombardo, Susana Castillo, Oliver Hupe, Marcus Magnor